Not generating valid RTP-Info headers for RTSP 2.0

The same of course also applies to the parsing in rtspsrc.

In RTSP 1.0 the RTP-Info header basically looks like

RTP-Info: url=rtsp://foo.com/bar.avi/streamid=0;seq=45102,
          url=rtsp://foo.com/bar.avi/streamid=1;seq=30211

In RTSP 2.0 it includes the SSRC and a colon (and can include information for multiple SSRC per URL), and it requires double quotes around the URL:

RTP-Info: url="rtsp://example.com/foo/audio" ssrc=0A13C760:seq=45102;rtptime=12345678,
          url="rtsp://example.com/foo/video" ssrc=9A9DE123:seq=30211;rtptime=29567112

Compare https://tools.ietf.org/html/rfc2326#page-58 and https://tools.ietf.org/html/rfc7826#section-20.2.3

CC @thiblahute