[client] stop the cursorThread if video feed is disabled

The cursorThread prevents the host from going to sleep when the
video feed is disabled as it's subscribed to the cursor queue. Stopping
the cursorThread will unsubscribe from the queue and allow the host
application to disable capture.

client/src/keybind.c

@@ -43,9 +43,15 @@ static void bind_video(int sc, void * opaque)
   );
 
   if (g_state.stopVideo)
+  {
+    core_stopCursorThread();
     core_stopFrameThread();
+  }
   else
+  {
+    core_startCursorThread();
     core_startFrameThread();
+  }
 }
 
 static void bind_rotate(int sc, void * opaque)