libutils: refbase: jellybean mr1 compat

Change-Id: Ideee0c3814a17b47f70fd612d27067fe19ae698d
adb: Fix backup fallback

 * Check for existence of binary first

Change-Id: I5c1884655ae031f51cb935221ae7870b016e259d

Conflicts:
	adb/backup_service.c