client: error out on non-aggregate control
client: error out on non-aggregate control

We require aggregate control (for now) for PLAY, PAUSE and TEARDOWN.

Lachann/gst-rtsp-server,surround-io/gst-rtsp-server,hsteinhaus/gst-rtsp-server,hsteinhaus/gst-rtsp-server,barisdemiray/gst-rtsp-server,surround-io/gst-rtsp-server,surround-io/gst-rtsp-server,Lachann/gst-rtsp-server,thaytan/gst-rtsp-server,thaytan/gst-rtsp-server,Lachann/gst-rtsp-server,barisdemiray/gst-rtsp-server,barisdemiray/gst-rtsp-server,thaytan/gst-rtsp-server,hsteinhaus/gst-rtsp-server