queue2: update buffering when changing capacity
queue2: update buffering when changing capacity

When the capacity of the queue changes, make sure we post an updated buffering
message because we might suddenly have completed the buffering stage.

Lachann/gstreamer,krieger-od/gstreamer,lubosz/gstreamer,krieger-od/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,lubosz/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,cablelabs/gstreamer,surround-io/gstreamer,justinjoy/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,Lachann/gstreamer,lubosz/gstreamer,justinjoy/gstreamer,cablelabs/gstreamer,krichter722/gstreamer,ensonic/gstreamer,ensonic/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,krichter722/gstreamer,lovebug356/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,surround-io/gstreamer,justinjoy/gstreamer,StreamUtils/gstreamer,jpakkane/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,centricular/gstreamer,krichter722/gstreamer,centricular/gstreamer,mparis/gstreamer,lovebug356/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,ensonic/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,lubosz/gstreamer,lubosz/gstreamer,centricular/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,cfoch/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,mparis/gstreamer,justinjoy/gstreamer,surround-io/gstreamer,shelsonjava/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,mparis/gstreamer,cablelabs/gstreamer,Lachann/gstreamer,ensonic/gstreamer,krichter722/gstreamer,jpakkane/gstreamer,lovebug356/gstreamer,Lachann/gstreamer,cfoch/gstreamer,jpxiong/gstreamer,cfoch/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,krieger-od/gstreamer,ensonic/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer