callmodel: reintroduce old signals to avoid race conditions during call

- Fixes a possibly null call object preventing the emission of
  remotePreviewStarted and resulting in no distant renderer
- This is only until the win32/macOS clients migrate completely
  to AVModel

Change-Id: I167ca480739664a14aac4da0f1dc16d8e18623b6

src/callmodel.cpp

@@ -166,9 +166,10 @@ void CallModelPrivate::init()
     CallManagerInterface& callManager = CallManager::instance();
 #ifdef ENABLE_VIDEO
     VideoManager::instance();
-#endif                                                                                                                        */
+#endif
 
-    connect(&CategorizedHistoryModel::instance(),SIGNAL(newHistoryCall(Call*)),this,SLOT(slotAddPrivateCall(Call*)));
+    connect(&callManager, SIGNAL(callStateChanged(QString, QString, int)), this, SLOT(slotCallStateChanged(QString, QString, int)), Qt::QueuedConnection);
+    connect(&callManager, SIGNAL(recordingStateChanged(QString, bool)), this, SLOT(slotRecordStateChanged(QString, bool)), Qt::QueuedConnection);
 
     registerCommTypes();