Remove groups from chains and elements from groups when they are destroyed.
Remove groups from chains and elements from groups when they are destroyed.

Original commit message from CVS:
Remove groups from chains and elements from groups when they are destroyed.

cfoch/gstreamer,justinjoy/gstreamer,ahmedammar/platform_external_gst_gstreamer,collects/gstreamer,jpakkane/gstreamer,jpxiong/gstreamer,mrchapp/gstreamer,krieger-od/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,mparis/gstreamer,Lachann/gstreamer,ylatuya/gstreamer,cfoch/gstreamer,collects/gstreamer,cablelabs/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,mparis/gstreamer,Distrotech/gstreamer,magcius/gstreamer,magcius/gstreamer,ensonic/gstreamer,collects/gstreamer,jpxiong/gstreamer,surround-io/gstreamer,ahmedammar/platform_external_gst_gstreamer,lovebug356/gstreamer,Lachann/gstreamer,jpakkane/gstreamer,ensonic/gstreamer,krichter722/gstreamer,krieger-od/gstreamer,krichter722/gstreamer,drothlis/gstreamer,mparis/gstreamer,lovebug356/gstreamer,centricular/gstreamer,ahmedammar/platform_external_gst_gstreamer,drothlis/gstreamer,cfoch/gstreamer,lovebug356/gstreamer,surround-io/gstreamer,Lachann/gstreamer,lubosz/gstreamer,shelsonjava/gstreamer,ensonic/gstreamer,lubosz/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,justinjoy/gstreamer,centricular/gstreamer,collects/gstreamer,justinjoy/gstreamer,jpxiong/gstreamer,mrchapp/gstreamer,surround-io/gstreamer,collects/gstreamer,ahmedammar/platform_external_gst_gstreamer,ylatuya/gstreamer,jpakkane/gstreamer,justinjoy/gstreamer,centricular/gstreamer,drothlis/gstreamer,centricular/gstreamer,cfoch/gstreamer,lubosz/gstreamer,lubosz/gstreamer,ensonic/gstreamer,Distrotech/gstreamer,krichter722/gstreamer,Lachann/gstreamer,Lachann/gstreamer,justinjoy/gstreamer,cablelabs/gstreamer,lubosz/gstreamer,ensonic/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,cablelabs/gstreamer,jpakkane/gstreamer,Distrotech/gstreamer,mrchapp/gstreamer,drothlis/gstreamer,magcius/gstreamer,cablelabs/gstreamer,krieger-od/gstreamer,ahmedammar/platform_external_gst_gstreamer,cfoch/gstreamer,ylatuya/gstreamer,jpakkane/gstreamer,krichter722/gstreamer,krieger-od/gstreamer,krichter722/gstreamer,mparis/gstreamer,magcius/gstreamer,lovebug356/gstreamer,ylatuya/gstreamer,ylatuya/gstreamer,mrchapp/gstreamer,Distrotech/gstreamer,StreamUtils/gstreamer,magcius/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,mrchapp/gstreamer,surround-io/gstreamer,surround-io/gstreamer,mparis/gstreamer,jpxiong/gstreamer,drothlis/gstreamer,krieger-od/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,Distrotech/gstreamer