Camera: properly detect multiple cameras when using the camcorder

Currently, the option to switch between front and rear cameras is
available whether or not the device has multiple cameras. It does
work correctly when in camera (still) mode , the bug only happens
in the video camera.

Change-Id: I66d1a01ff496ed03544049bd1d03881fbef3a07f
Merge "Camera: properly detect multiple cameras when using the camcorder" into cm-10.1