docs: fix location in user's home directory where GStreamer looks for plugins
docs: fix location in user's home directory where GStreamer looks for plugins

It's based on the xdg user data dir now in 1.0.

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