vsp deviceid optimize

[tanjiangyu-ghca]

What this PR does / why we need it:

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

Release note:

[codecov]

Codecov Report

Merging #500 (5641736) into vsp_host (0d9d9f9) will increase coverage by 0.01%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##           vsp_host     #500      +/-   ##
============================================
+ Coverage     70.45%   70.47%   +0.01%     
============================================
  Files           180      180              
  Lines         18827    18827              
  Branches       2785     2785              
============================================
+ Hits          13265    13268       +3     
+ Misses         4698     4694       -4     
- Partials        864      865       +1     

Impacted Files	Coverage Δ
delfin/drivers/hitachi/vsp/rest_handler.py	40.40% <0.00%> (ø)
delfin/drivers/fake_storage/__init__.py	93.63% <0.00%> (+0.76%)	⬆️