webos-image: pmloglib=r6

:Release Notes:
Fix pmloglib recipe to correctly pass the pre-release build indicator
flag (WEBOS_DISTRO_PRERELEASE) value to CMake.

:Detailed Notes:
The WEBOS_DISTRO_PRERELEASE bitbake variable was not properly passed to
CMake. As a result, the disabling of parsing context specific log files
did not happen in the trial production build 459.

:Testing Performed:
Compiled and tested that individual context log files are not generated
in /var/log/ .

:QA Notes:

:Issues Addressed:
[GF-55383] Enable uploading of crashes and analytic logs
[GF-56607] CCC: pmloglib=r6

Open-webOS-DCO-1.0-Signed-off-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>
Change-Id: Ia03442a46dfb6bf0ad7046dcd0e647cb99296581
Reviewed-on: https://g2g.palm.com/4254
Reviewed-by: DCO Verification
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Tested-by: Herb Kuta <herb.kuta@lge.com>
Reviewed-by: Keith Derrick <keith.derrick@lge.com>
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Jongho Kim <jongho1208.kim@lge.com>
Tested-by: Jongho Kim <jongho1208.kim@lge.com>