[pytest/coverage]: add coverage for all scripts

[lguohan]

Signed-off-by: Guohan Lu lguohan@gmail.com

- What I did
add coverage for all scripts

- How I did it

- How to verify it

---------- coverage: platform linux2, python 2.7.16-final-0 ----------
Name                                       Stmts   Miss  Cover
--------------------------------------------------------------
acl_loader/__init__.py                         0      0   100%
acl_loader/main.py                           541    367    32%
clear/__init__.py                              0      0   100%
clear/bgp_frr_v6.py                           44     44     0%
clear/bgp_quagga_v4.py                        44     44     0%
clear/bgp_quagga_v6.py                        44     44     0%
clear/main.py                                179    106    41%
config/__init__.py                             0      0   100%
config/aaa.py                                132     82    38%
config/config_mgmt.py                        345    116    66%
config/feature.py                             25      5    80%
config/main.py                              2280   1683    26%
config/mlnx.py                               134     93    31%
config/nat.py                                680    570    16%
connect/__init__.py                            0      0   100%
connect/main.py                               55     55     0%
consutil/__init__.py                           0      0   100%
consutil/lib.py                               79     79     0%
consutil/main.py                              70     70     0%
counterpoll/__init__.py                        0      0   100%
counterpoll/main.py                          126    126     0%
crm/__init__.py                                0      0   100%
crm/main.py                                  289    289     0%
debug/__init__.py                              0      0   100%
debug/main.py                                153    153     0%
fwutil/__init__.py                             5      5     0%
fwutil/lib.py                                474    474     0%
fwutil/log.py                                 44     44     0%
fwutil/main.py                               243    243     0%
pcieutil/__init__.py                           0      0   100%
pcieutil/main.py                              75     75     0%
pddf_fanutil/__init__.py                       0      0   100%
pddf_fanutil/main.py                         182    182     0%
pddf_ledutil/__init__.py                       0      0   100%
pddf_ledutil/main.py                          60     60     0%
pddf_psuutil/__init__.py                       0      0   100%
pddf_psuutil/main.py                         203    203     0%
pddf_thermalutil/__init__.py                   0      0   100%
pddf_thermalutil/main.py                     104    104     0%
pfcwd/__init__.py                              0      0   100%
pfcwd/main.py                                198    198     0%
psuutil/__init__.py                            0      0   100%
psuutil/main.py                               66     66     0%
scripts/aclshow                              127     13    90%
scripts/db_migrator.py                       189    189     0%
scripts/dropconfig                           215    103    52%
scripts/dropstat                             216     21    90%
scripts/dump_nat_entries.py                   12     12     0%
scripts/fast-reboot-dump.py                  204    204     0%
scripts/filter_fdb_entries.py                 87     87     0%
scripts/gearboxutil                          131     21    84%
scripts/intfstat                             194     42    78%
scripts/intfutil                             314    100    68%
scripts/port2alias                            32      5    84%
scripts/psushow                               59      9    85%
scripts/route_check.py                       172    172     0%
scripts/sfpshow                              168     36    79%
scripts/update_json.py                        35     35     0%
sfputil/__init__.py                            0      0   100%
sfputil/main.py                              338    338     0%
show/__init__.py                               0      0   100%
show/bgp_frr_v4.py                            36     36     0%
show/bgp_frr_v6.py                            33     33     0%
show/bgp_quagga_v4.py                         20     20     0%
show/bgp_quagga_v6.py                         15     15     0%
show/feature.py                               34      0   100%
show/main.py                                1892   1359    28%
show/mlnx.py                                  80     62    23%
sonic_installer/__init__.py                    0      0   100%
sonic_installer/bootloader/__init__.py         9      9     0%
sonic_installer/bootloader/aboot.py          136    136     0%
sonic_installer/bootloader/bootloader.py      32     32     0%
sonic_installer/bootloader/grub.py            60     60     0%
sonic_installer/bootloader/onie.py            27     27     0%
sonic_installer/bootloader/uboot.py           61     61     0%
sonic_installer/common.py                     21     21     0%
sonic_installer/exception.py                   2      2     0%
sonic_installer/main.py                      412    412     0%
ssdutil/__init__.py                            0      0   100%
ssdutil/main.py                               50     50     0%
utilities_common/__init__.py                   0      0   100%
utilities_common/cli.py                       26      9    65%
utilities_common/db.py                         5      0   100%
utilities_common/intf_filter.py               30     18    40%
utilities_common/netstat.py                   35     15    57%
utilities_common/util_base.py                 32     32     0%
watchdogutil/__init__.py                       0      0   100%
watchdogutil/main.py                          54     54     0%
--------------------------------------------------------------
TOTAL                                      12469   9430    24%
Coverage HTML written to dir htmlcov
Coverage XML written to file coverage.xml

- Previous command output (if the output of a command-line utility has changed)

- New command output (if the output of a command-line utility has changed)

[lguohan]

add coverage for all scripts. let's use this to improve our unit test coverage in this repo.