Fix a crash when using UVWFlagger in a GainCal step
The GainCal step forgets to set that it needs UVW values when a UVWFlagger is part of the GainCal step. Reported by Bharat.
The GainCal step forgets to set that it needs UVW values when a UVWFlagger is part of the GainCal step. Reported by Bharat.