SnapdragonCamera: Hide the preview cover when preview has started

The preview cover was shown when onPause, but didn't hide after
resume. That caused the video preview turned to black screen.

After the camera preview starts, hide the preview cover if it is
still showing.

Change-Id: I79fdcd45d46d7c083a132e864bbf42649b100ae4
CRs-Fixed: 865933
2 files changed