Merge "Fix shutdown and eliminate those annoying "failed to post..." logs." into jb-mr1-dev

void WifiDisplaySource::disconnectClient(status_t err) {

    if (mClientSessionID != 0) {

        if (mClientInfo.mPlaybackSession != NULL) {

            looper()->unregisterHandler(mClientInfo.mPlaybackSession->id());

            sp<PlaybackSession> playbackSession = mClientInfo.mPlaybackSession;

            mClientInfo.mPlaybackSession.clear();

            playbackSession->destroy();

            looper()->unregisterHandler(playbackSession->id());

        }

        mNetSession->destroySession(mClientSessionID);