grammar.y: fix childproxy code
grammar.y: fix childproxy code

It takes GObject and not GstObject now

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