Add compatibility for mojomail-pop

:Release Notes:
mojomail-pop is using old log format.
This change allow to keep mojomail-pop in compailable state.

:Detailed Notes:
Add static variable used by mojomail-pop for logging.

:Testing Performed:
tested on local build

:QA Notes:

:Issues Addressed:
[GF-40978] mojodb log messages wrong formatting

Open-webOS-DCO-1.0-Signed-off-by: Igor Kuksyuk <igor.kuksiuk@lge.com>

Change-Id: I4a78ca505f452966d547df3d467319e6bb271f50
Reviewed-on: https://g2g.palm.com/4238
Reviewed-by: DCO Verification
Reviewed-by: Igor Kuksyuk <igor.kuksiuk@lge.com>
Tested-by: Igor Kuksyuk <igor.kuksiuk@lge.com>
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>