The reason we need this count is a new CameraService::connect() request may
come in while the previous Client's destructor has not been run or is still
running. If the last strong reference of the previous Client is gone but
destructor has not been run, we should not allow the new Client to be created
because we need to wait for the previous Client to tear down the hardware
first.
to CameraService::onTransact() method during development. Later on
the entire onTransact() method was #ifdef'd out, which inadvertently
omitted the permissions check code. This change restores the code.
