camera: add a workaround for slow camera startup

* On certain devices, the first camera initialisation
  takes long, and fails sometimes.
* Add an app that opens and closes the camera on boot,
  so that when the user opens a camera app, it has
  already been initialised and will work.

Signed-off-by: Chirayu Desai <cdesai@cyanogenmod.org>
Change-Id: I0623a0777ad83741c1c36355dffa8adf3a510df3