tests: baseparse: set_sink_caps vfunc should't take ownership of the caps
tests: baseparse: set_sink_caps vfunc should't take ownership of the caps

https://bugzilla.gnome.org/show_bug.cgi?id=737762

jpxiong/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,mparis/gstreamer,mparis/gstreamer,krichter722/gstreamer,mparis/gstreamer,krichter722/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,mparis/gstreamer,jpxiong/gstreamer,mparis/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,centricular/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,jpxiong/gstreamer