Error when calibrating with only a vis model

[SpheMakh]

Wan't to calibrate using the clean model (in MODEL_DATA column) from a previous imaging step, but calico-stefcal doesn't allow this unless a tigger LSM is also provided.

WARNING: unable to determine delta-UVW in tile Vis_Data_0_0_0_0_1_0, setting to 0.
Traceback (most recent call last):
  File "/usr/bin/meqtree-pipeliner.py", line 176, in <module>
    res = func(mqs,None,wait=True);
  File "/usr/local/lib/python2.7/dist-packages/Cattery/Calico/calico-stefcal.py", line 381, in _run_stefcal
    mqs.execute('VisDataMux',mssel.create_io_request(),wait=wait);
  File "/usr/lib/python2.7/dist-packages/Timba/Apps/meqserver.py", line 173, in execute
    return self.meq('Node.Execute',rec,wait=wait);
  File "/usr/lib/python2.7/dist-packages/Timba/Apps/meqserver.py", line 126, in meq
    msg = self.await(replyname,resume=True,timeout=wait);
  File "/usr/lib/python2.7/dist-packages/Timba/Apps/multiapp_proxy.py", line 525, in await
    res = self._pwp.await(self._rcv_prefix + what,timeout=await_timeout,resume=resume);
  File "/usr/lib/python2.7/dist-packages/Timba/octopussy.py", line 434, in await
    self.resume_events();
  File "/usr/lib/python2.7/dist-packages/Timba/octopussy.py", line 414, in resume_events
    self._lock.release();
  File "/usr/lib/python2.7/threading.py", line 204, in release
    raise RuntimeError("cannot release un-acquired lock")
RuntimeError: cannot release un-acquired lock