queue2: update segment position on GAP events to calculate levels properly
queue2: update segment position on GAP events to calculate levels properly

https://bugzilla.gnome.org/show_bug.cgi?id=737498

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