droidenc: try to force a keyframe if we get asked to do so and warn if we fail
droidenc: try to force a keyframe if we get asked to do so and warn if we fail

sailfishos/gst-droid,foolab/gst-droid,mlehtima/gst-droid,mlehtima/gst-droid,foolab/gst-droid,sledges/gst-droid,sledges/gst-droid,sledges/gst-droid