Pmcertificatemgr: Coverity bug fixes

:Release Notes:
Coverity tool bug fixes.

:Detailed Notes:
Addressed issues categorized under following types-
memory leak, resource leak, calling risky functions,
Null checks, return value checks, logically dead codes,
wrong sized arguments.

Note that the private library function makeUnique was extremely
dangerous. There is no indication thay anyone was using it, so
it has been removed.

:Testing Performed:
Compiled locally and tested on official build.

:QA Notes:

:Issues Addressed:
[GF-53261] pmcertificatemgr: fix coverity issues
Open-webOS-DCO-1.0-Signed-off-by: ashish.sadre <ashish.sadre@lge.com>

Change-Id: I91cd81bcbf3f8a748f1c9145dc9146ec206c2ce5
Open-webOS-DCO-1.0-Signed-off-by: Keith Derrick <keith.derrick@lge.com>
Reviewed-on: https://g2g.palm.com/4077
Reviewed-by: DCO Verification
Reviewed-by: Keith Derrick <keith.derrick@lge.com>
Tested-by: Keith Derrick <keith.derrick@lge.com>