omx: fix hacks leak on class init
omx: fix hacks leak on class init

varunkumara/test-repo,varunkumara/test-repo,CapOM/gst-omx,varunkumara/test-repo,CapOM/gst-omx,GStreamer/gst-omx,GStreamer/gst-omx,GStreamer/gst-omx,CapOM/gst-omx