Force a factory reset if device has run out of space

:Release Notes:
When db8 starts, it check available disk space on device. If not enough disk space avaialbe,
upstart script ask device to reset to initial factory settings and wipe all data.

:Detailed Notes:
Check available disk space on /var/db partition on db8 start
If partition have less then 31M, reset device to initial settings

:Testing Performed:
Compiled and tested on device

:QA Notes:

:Issues Addressed:
[GF-53734] DB8 needs to force a factory reset if it has run out of space

Open-webOS-DCO-1.0-Signed-off-by: Maksym Sditanov <maxim.sditanov@lge.com>

Change-Id: I64a4c2f22a6054b5935fbbf6aa4bfd0a5ee273bd
Reviewed-on: https://g2g.palm.com/4295
Reviewed-by: DCO Verification
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>
Reviewed-by: Oleksii Uratkin <oleksii.urathkin@lge.com>