kes Rework next_vol and autoprune a bit due to failure in

     recycle-test.  prune_volumes() now returns no status,
     but should prune at least one Volume, if possible.
kes  Modify check_if_volume_valid_or_recyclable to reject a
     volume with Recycle set off.
kes  Modify prune_volumes() to continue if volume Recycle is off
     or if the volume has expired. Add more debug.