[evlatests] no change card

[Gustaaf van Moorsel]

Yesterday I tested the 'no change' option in the Modcomp-free system.
This option allows the user to switch to a different scan while keeping
the LO settings unchanged.  This option was broken in the transition
system and the hope was it would work again in the Modcomp-free system.

Indeed, it does.  Two consecutive scans end up with exactly the same
frequency.  This is an useful result since many users like to use this
option and were unable to do so for a while.

Gustaaf