Revert "oggmux: fix pad leak"

This reverts commit 5df30c1b905edce16f2258e414a0a4afb540d0f1.

I must have dreamt the Valgrind logs, reverting this reintroduces
no leak, and gets rid of the test failures it introduced :S

ext/ogg/gstoggmux.c

@@ -287,8 +287,6 @@ gst_ogg_mux_finalize (GObject * object)
     ogg_mux->collect = NULL;
   }
 
-  gst_object_unref (ogg_mux->srcpad);
-
   G_OBJECT_CLASS (parent_class)->finalize (object);
 }