queue2: fix memory leak
queue2: fix memory leak

unmap the buffer memory on errors.

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