camera: Fixes for race conditions in abnormal snapshot stop.

Change-Id: Iba20800baee92dcd59ae6edb96e7dc1953c83a88
Bug: 12467743
Bug: 11021907
Camera: Fix race condition in snapshot.

Change-Id: I917994f3bb4663eb33ffa2c76754947f70f3cd5e
Bug: 13620972