Closes-Bug: #1400162
-Issue: In 14.0.4, storage stats Subprocess Popen
        returns the following warning on all calls:
        "['libust[38153/38153]: Warning: HOME environment
        variable not set. Disabling LTTng-UST per-user
        tracing. (in setup_local_apps() at
        lttng-ust-comm.c:305)"
-Fix: copied current environment variables and
      added "HOME" variable. This newly created
      environment is then passed to Popen call
      to solve the above mentioned issue
-Test: Verified the changes on HA cluster

Change-Id: I25d4a84d63836631db69d8d5169dcdd83484c047
Merge "Closes-Bug: #1400162 -Issue: In 14.0.4, storage stats Subprocess Popen         returns the following warning on all calls:         "['libust[38153/38153]: Warning: HOME environment         variable not set. Disabling LTTng-UST per-user         tracing. (in setup_local_apps() at         lttng-ust-comm.c:305)" -Fix: copied current environment variables and       added "HOME" variable. This newly created       environment is then passed to Popen call       to solve the above mentioned issue -Test: Verified the changes on HA cluster"