Fix all possible memory leaks

:Release Notes:
Fix memory leaks based on valgrind report.

:Detailed Notes:
With the recent fixes in WCA, connman and wpas, the memory usage of WCA
doesn't go up much unless the WiFi settings UI page is opened where the
network list is being continuously updated. So with the fixes in the change,
even the memory usage with UI goes down considerably.

:Testing Performed:
Monitored the memory consumption of WCA using "top -p <PID>" program for
couple of hours.

:Issues Addressed:
[GF-7993] webos-conman-adapter memory consumption keeps going up when TV
          is idle

Open-webOS-DCO-1.0-Signed-off-by: Simon Busch <simon.busch@lge.com>

Change-Id: Ieafa2089e66a00ea398dc74b89a05f646ca3a09b
Reviewed-on: https://g2g.palm.com/3680
Reviewed-by: Build Verification
Reviewed-by: Sapna Todwal <sapna.todwal@lge.com>
Tested-by: Sapna Todwal <sapna.todwal@lge.com>