[evlatests] Master LO Rack -- L350, L356 adjustments

[Keith Morris]

We reverted the L350 MIB code to version 0.999, which was the original
short-term fix to the NTP request problem.  Lab tests showed that the
later MIB versions, 1.000 and 1.001, which addressed problems in the MIB's
IGMP packet parsing, appeared to cause missing 60-second flag edges, while
version 0.999 did not.  We will allow this to run for a week or so, while
monitoring the WIDAR timecode faults.

In addition, we cleaned the fibers between the L350-2 and the master rack
optical switch.  This L350 had been producing WIDAR timecode CRC errors,
which went away when we switched to L350-1.  We confirmed that the
timecode appeared valid, as reported by the XBB LED display, but it will
require longer operation to determine whether the CRC error problem has
been fixed.

The L356 firmware was upgraded to the version that is running in the lab. 
In the lab, this firmware version fixes the GPS/PPS offset measurement
problem.  However, the MIB version, particularly the logical points file,
that accompanies this firmware version, was not available to install.  The
monitor points read as before, with correct drift measurements riding on
an arbitrary offset.  So the L356 functionality is unchanged, for the
moment.  When Hichem returns, we will investigate the MIB/FPGA
interaction, and possibly install the lab L356.

The GPS-Rubidium counter offset is in the 700ns range.  This will probably
continue to change over the next few hours, as the Master Rack temperature
stabilizes.  I have the logs of the daily 8am/4pm offset measurements,
going back to last Wednesday, when we started documenting these
measurements, and we will continue to do that at least until the system is
restored to maser reference.