QAmqpChannel: Emit closed signal when server closes.

When we initiate a Close, we get a CloseOk in response and on receipt of
the CloseOk, we mark the channel as closed and emit a signal to notify
everyone else.

Great.  Now what happens when the server closes the channel?  We emit a
CloseOk, then… nothing.  We do nothing.  This fixes this problem, moving
the notification/marking logic to a new function and calling that on
both Close (sent from server) and CloseOk.

src/qamqpchannel.cpp

@@ -203,9 +203,17 @@ void QAmqpChannelPrivate::close(const QAmqpMethodFrame &frame)
     QAmqpMethodFrame closeOkFrame(QAmqpFrame::Channel, miCloseOk);
     closeOkFrame.setChannel(channelNumber);
     sendFrame(closeOkFrame);
+
+    // notify everyone that the channel was closed on us.
+    notifyClosed();
 }
 
 void QAmqpChannelPrivate::closeOk(const QAmqpMethodFrame &)
+{
+    notifyClosed();
+}
+
+void QAmqpChannelPrivate::notifyClosed()
 {
     Q_Q(QAmqpChannel);
     Q_EMIT q->closed();

src/qamqpchannel_p.h

@@ -44,6 +44,7 @@ public:
     void flow(bool active);
     void flowOk();
     void close(int code, const QString &text, int classId, int methodId);
+    void notifyClosed();
 
     // reimp MethodHandler
     virtual bool _q_method(const QAmqpMethodFrame &frame);