Camera3: Adding checks for stream handle

In certain conditions it is possible that flush
is called before the stream handles are initialized.
Ex: between configureStreams & processCaptureRequest
Adding more checks for such cases.

Bug: 23186410
Ack by: Mansoor Aftab

Change-Id: I10c5ef691ba12f9cf98363613ad28070d82514c3
2 files changed