Return errors in postRestore API method for bad params

:Release Notes:
 Input parameter validation is done.

:Detailed Notes:

:Testing Performed:
 Compiled locally and tested in device

:QA Notes:

:Issues Addressed:
 [GF-9750] Passing no paramter in the function is throwing exception

Open-webOS-DCO-1.0-Signed-off-by: Yasaswini A Y <yasaswini.ay@lge.com>

Change-Id: I5dea46bedcc30153eeaa565ed0c70bc868a6306f
Reviewed-on: https://g2g.palm.com/3315
Reviewed-by: Build Verification
Reviewed-by: Roger Stringer <roger.stringer@lge.com>
Tested-by: Roger Stringer <roger.stringer@lge.com>