[evlatests] EVLA hardware

[Rob Long]

The D304 and T303 (U/X converter) have been removed from ant 18 for 
troubleshooting.  I did not get to look any further into the weird 
polarization problem at L-band.  The external cabling looks fine so we 
will probably have to check the L/S/C converter more closely.

I swapped the L302s in ant 13 with each other.  L302-1 is now L302-2 and 
  vice versa.  The original L302-1 would not lock at the default L-band 
frequency for A/C, but locks fine at all default frequencies for B/D. 
This is not the best solution, but will work for all bands/default 
frequencies until we make some decisions on the L302s.  L-band signals 
going into the DTS modules looked good at all IFs and switched power at 
the T5s also looked fine.

Rob