server: Emit client-connected signal earlier
server: Emit client-connected signal earlier

Emit client-connected before the client ref is given to a GSource,
otherwise client-connected can be emitted after the client object has
been freed.

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