omxvideoenc: fix a memory leak in gst_omx_video_enc_getcaps
omxvideoenc: fix a memory leak in gst_omx_video_enc_getcaps

https://bugzilla.gnome.org/show_bug.cgi?id=725826

leio/gst-omx,CapOM/gst-omx,surround-io/gst-omx,ismelykh/gst-omx-deinterlace,leio/gst-omx,freedesktop-unofficial-mirror/gstreamer__gst-omx,pliu6/gst-omx,varunkumara/test-repo,varunkumara/test-repo,GStreamer/gst-omx,pliu6/gst-omx,renesas-rcar/gst-omx,varunkumara/test-repo,CapOM/gst-omx,surround-io/gst-omx,renesas-rcar/gst-omx,freedesktop-unofficial-mirror/gstreamer__gst-omx,CapOM/gst-omx,GStreamer/gst-omx,ismelykh/gst-omx-deinterlace,GStreamer/gst-omx,renesas-rcar/gst-omx