17. Reweight visibilities

Calculate data weights based on st. dev. within each spw.

No pipeline QA for this task.
vis
['/scratch/VLA-2015/dataset-1/Dataset-1-Qband.ms', '/scratch/VLA-2015/dataset-1/Dataset-1-Kaband.ms']
Start time
2018-11-28 08:26:42.519
End
2018-11-28 08:39:03.555
Duration
0:12:21.037

CASA logs for stage 17