client: let stream check supported transport
client: let stream check supported transport

Delegate the check if a transport is allowed to the stream.

See https://bugzilla.gnome.org/show_bug.cgi?id=720696

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