Fix cppcheck issues

:Release Notes:
Fixed issues detected by cppcheck

:Detailed Notes:

:Testing Performed:
Trivial change

:QA Notes:

:Issues Addressed:
[ANG-854] filecache: Investigate and fix issues detected by cppcheck

Open-webOS-DCO-1.0-Signed-off-by: Mykola Kryvonos <mykola.kryvonos@lge.com>

Change-Id: I156d42cb3cf6b4e0100a4d0b281cedbf8f25e424
Reviewed-on: https://g2g.palm.com/4700
Reviewed-by: DCO Verification
Reviewed-by: Mykola Kryvonos <mykola.kryvonos@lge.com>
Tested-by: Mykola Kryvonos <mykola.kryvonos@lge.com>
Reviewed-by: Andrii Zora <andrii.zora@lge.com>
Reviewed-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>