Set default value for cmake variable

:Release Notes:

:Detailed Notes:
Bug fix for enabling logging in open webOS and other layers

:Testing Performed:
Verified that logging is enabled in open webOS and disabled
conditionally

:QA Notes:

:Issues Addressed:
[CTO-540] PmLog not working in open webOS and other layers

Open-webOS-DCO-1.0-Signed-off-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>

Change-Id: I78c69a206739f78598f2bd3ee812cd1927b7461d
Reviewed-on: https://g2g.palm.com/6412
Reviewed-by: DCO Verification
Reviewed-by: Ed Chejlava <ed.chejlava@lge.com>
Reviewed-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Tested-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Merge branch 'develop'