Add namespace of the process in the coredump filename. (sonic-net#1091)

Look for namespace of this process in crashing process's environ file.If any, add it to core filename as
< binary name >.< timestamp >.< local pid inside container >.< ns > .core.gz.
e.g. orchagent.1599073263.45.5.core.gz <-- 5 is the asic namespace.

For processes that don't have asic namespace, there is no change.
e.g. snmpd.1599073245.27.core.gz

The /etc/sysctl.conf kernel.core_pattern is set to pass pid in host
as last arg.

scripts/coredump-compress

@@ -2,9 +2,16 @@
 
 # Collect all parameters in order and build a file name prefix
 PREFIX=""
-while [[ $# > 0 ]]; do
+while [[ $# > 1 ]]; do
     PREFIX=${PREFIX}$1.
     shift
 done
 
+if [ $# > 0 ]; then
+    ns=`xargs -0 -L1 -a /proc/${1}/environ | grep -e "^NAMESPACE_ID" | cut -f2 -d'='`
+    if [ ! -z ${ns} ]; then
+        PREFIX=${PREFIX}${ns}.
+    fi
+fi
+
 /bin/gzip -1 - > /var/core/${PREFIX}core.gz