testegl: add a comment for the parse command
testegl: add a comment for the parse command

See https://bugzilla.gnome.org/show_bug.cgi?id=728940

ismelykh/gst-omx-deinterlace,GStreamer/gst-omx,freedesktop-unofficial-mirror/gstreamer__gst-omx,varunkumara/test-repo,renesas-rcar/gst-omx,CapOM/gst-omx,varunkumara/test-repo,leio/gst-omx,freedesktop-unofficial-mirror/gstreamer__gst-omx,leio/gst-omx,renesas-rcar/gst-omx,CapOM/gst-omx,renesas-rcar/gst-omx,CapOM/gst-omx,GStreamer/gst-omx,surround-io/gst-omx,ismelykh/gst-omx-deinterlace,surround-io/gst-omx,varunkumara/test-repo,GStreamer/gst-omx