clock: Return FALSE in all paths that don't set out parameters in gst_clock_add_observation_unapplied()
clock: Return FALSE in all paths that don't set out parameters in gst_clock_add_observation_unapplied()

It returned TRUE when regression failed, while not setting any of the out
parameters. This caused uninitialized data from the stack to be used for
setting the clock calibration.

StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer