rtpjitterbuffer: Ensure to not take caps with the wrong pt for getting the clock-rate
rtpjitterbuffer: Ensure to not take caps with the wrong pt for getting the clock-rate

Especially the caps on the pad might be out of date, and the new caps would be
provided for the current pt via the request-pt-map signal.

https://bugzilla.gnome.org/show_bug.cgi?id=765689

Kurento/gst-plugins-good,Kurento/gst-plugins-good,Kurento/gst-plugins-good,Kurento/gst-plugins-good,Kurento/gst-plugins-good