rtspsrc: Does not handle "Unsupported Transport" correctly with RTSP 2.0 and pipelined requests
Problem here is that we'd send a SETUP for each stream at once, and then they could all come back with "Unsupported Transport". For RTSP 1.0 we would try other transports then, for RTSP 2.0 this completely fails instead of trying other transports.
In addition, for RTSP 2.0 (and 1.0 actually!) we could provide the list of all transports we would support in the initial SETUP and let the server select something instead of probing via "Unsupported Transport" and trying multiple times.