element: remove base_class_finalize_func which is never called
element: remove base_class_finalize_func which is never called

Won't be called for static types, so no point keeping it around.

https://bugzilla.gnome.org/show_bug.cgi?id=765540

StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer