Remove main db in factory-reset case

:Release Notes:
Remove corrupted database after backup

:Detailed Notes:

:Testing Performed:
Tested on build-desktop

:QA Notes:

:Issues Addressed:
[BHV-1835] Factory Reset : Generate a lot of leveldb files irregularly

Open-webOS-DCO-1.0-Signed-off-by: Olexandr Solomakha <oleksander.solomakha@lge.com>

Change-Id: I549562d0fa46fd46aa28e2edc9970c95e44d35da
Reviewed-on: https://g2g.palm.com/5311
Reviewed-by: DCO Verification
Tested-by: Olexandr Solomakha <oleksander.solomakha@lge.com>
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>
Reviewed-by: Oleg Yablokov <oleg.yablokov@lge.com>