[evlatests] old correlator shutdown

[Ken Sowinski]

I am worried that Widar may have dependencies on old hardware that
we are unaware of.  To test that I suggest that on the day we stop
observing the old correlator and all the other stuff we propose to
abandon should be shut off, and in that state we spend some time to
verify that Widar still works with the twelve antennas then available.

If it works we have small assurance that we will not have extra
problems to debug when the system is restored weeks later.  If
it does not, we should try to understand why and be sure that it
will not be an issue when the system is restored.

After this, the dismantlement of old stuff may proceed.