Revert "rtptransceiver: Store the SSRC of the current stream"

This reverts commit d1da271f25.

It breaks the CI until the C# bindings are fixed.

ext/webrtc/gstwebrtcbin.c

@@ -277,14 +277,6 @@ gst_webrtcbin_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
     GST_DEBUG_OBJECT (parent,
         "On %" GST_PTR_FORMAT " checking negotiation? %u, caps %"
         GST_PTR_FORMAT, pad, check_negotiation, caps);
-
-    if (check_negotiation) {
-      WebRTCTransceiver *trans = WEBRTC_TRANSCEIVER (wpad->trans);
-      const GstStructure *s;
-
-      s = gst_caps_get_structure (caps, 0);
-      gst_structure_get_uint (s, "ssrc", &trans->current_ssrc);
-    }
   } else if (GST_EVENT_TYPE (event) == GST_EVENT_EOS) {
     check_negotiation = TRUE;
   }

ext/webrtc/webrtctransceiver.h

@@ -39,7 +39,6 @@ struct _WebRTCTransceiver
 
   TransportStream          *stream;
   GstStructure             *local_rtx_ssrc_map;
-  guint                     current_ssrc;
 
   /* Properties */
   GstWebRTCFECType         fec_type;