Camera2: make panoramic focus mode configurable

 - Port from cm-10.2
 - This allows for device maintainers to switch between
   INFINITY and CONTINUOUS_VIDEO focus modes.  Some devices
   do not support INFINITY so the image and preview are both
   out of focus.

Change-Id: I714ad4dc6c329565b9620ff12ebb830555a5d1ef

Conflicts:
	res/values/config.xml