Fix failure to swap ROMs if it contains filenames starting with a dot

Change-Id: I1af0667c4979f0dcc6bf49c2dd0be8535f249155
Use TWRP's restore functions when adding secondary ROM from backup

* Fixes problems with contexts

Change-Id: Ib11cf2f409e3e8295a9e52bf69d83c5f3b6d614c