Remove dangling media recorder client reference when setCamera() is used.

    // allow anyone to use camera

    LOGV("unlock (%p)", getCameraClient()->asBinder().get());

    status_t result = checkPid();

    if (result == NO_ERROR) mClientPid = 0;

    if (result == NO_ERROR) {

        mClientPid = 0;

        // we need to remove the reference so that when app goes

        // away, the reference count goes to 0.

        mCameraClient.clear();

    }

    return result;

}