rtph261pay: Fix compiler warning
rtph261pay: Fix compiler warning

gstrtph261pay.c: In function 'gst_rtp_h261_pay_class_init':
gstrtph261pay.c:1003:17: error: variable 'gobject_class' set but not used [-Werror=unused-but-set-variable]
   GObjectClass *gobject_class;

ikonst/gst-plugins-good,ikonst/gst-plugins-good,pexip/gst-plugins-good,rawoul/gst-plugins-good,GStreamer/gst-plugins-good,shelsonjava/gst-plugins-good,shelsonjava/gst-plugins-good,ikonst/gst-plugins-good,GStreamer/gst-plugins-good,Kurento/gst-plugins-good,froggatt/gst-plugins-good-m,hizukiayaka/gst-plugins-good,GStreamer/gst-plugins-good,StreamUtils/gst-plugins-good,sebras/gst-plugins-good,rawoul/gst-plugins-good,Kurento/gst-plugins-good,Kurento/gst-plugins-good,StreamUtils/gst-plugins-good,stfl/gst-plugins-good,chamois94/gst-plugins-good,Kurento/gst-plugins-good,GStreamer/gst-plugins-good,sebras/gst-plugins-good,StreamUtils/gst-plugins-good,hizukiayaka/gst-plugins-good,froggatt/gst-plugins-good-m,Kurento/gst-plugins-good,rawoul/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,shelsonjava/gst-plugins-good,chamois94/gst-plugins-good,StreamUtils/gst-plugins-good,sebras/gst-plugins-good,stfl/gst-plugins-good,chamois94/gst-plugins-good,stfl/gst-plugins-good,froggatt/gst-plugins-good-m,ikonst/gst-plugins-good,hizukiayaka/gst-plugins-good,shelsonjava/gst-plugins-good,GrokImageCompression/gst-plugins-good,pexip/gst-plugins-good,froggatt/gst-plugins-good-m,stfl/gst-plugins-good,GrokImageCompression/gst-plugins-good,GrokImageCompression/gst-plugins-good,hizukiayaka/gst-plugins-good,sebras/gst-plugins-good,rawoul/gst-plugins-good,pexip/gst-plugins-good,chamois94/gst-plugins-good,GrokImageCompression/gst-plugins-good