Camera: Fix instability during ZSL snapshot

- AF(for instance touch AF) could be started
  during ZSL mode. Currently the application
  will not wait for AF callback to come before
  proceeding with the snapshot. This depending
  on timing will lead to inconsistent camera
  application state where an AF callback could
  arrive during image capture and override the
  current state machine allowing the client to
  trigger capture again. The second capture
  will fail causing an exception.
- This patch will not let the camera application
  trigger snapshot when AF is still running
  during ZSL. Additionally it will unlock CAF
  after capture is done through a call to
  'cancelAutoFocus()'.

Change-Id: Id5ae8ff0b7c1576ac7c6221f09837929aefcea17
CRs-Fixed: 572996, 564453
2 files changed