client: remove watch of the second client after http tunnel setup
client: remove watch of the second client after http tunnel setup

The second client will be freed after the HTTP tunnel has been set up.
Make sure it's RTSP watch is never dispatched again.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=727488

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