Use command line argument to set path to mediadb

:Release Notes:
Instead of hardcoding it, allow the path to the mediadb directory to be
passed in on the command line.

:Detailed Notes:

:Testing Performed:
Compiled and tested locally.

:QA Notes:
This commit must be commited after https://g2g.palm.com/#/c/3959

:Issues Addressed:
[GF-51737] db8: Unhide directory /media/cryptofs/data/.db8

Open-webOS-DCO-1.0-Signed-off-by: Maksym Sditanov <maxim.sditanov@lge.com>
Change-Id: I469635d7c51eef7e6ab1ef61f60071623742ffa1
Reviewed-on: https://g2g.palm.com/3958
Reviewed-by: DCO Verification
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Tested-by: Herb Kuta <herb.kuta@lge.com>
Tested-by: Maksym Sditanov <maxim.sditanov@lge.com>
Reviewed-by: Maksym Sditanov <maxim.sditanov@lge.com>