[OBSICtec] Location revisions for four stations in past OBS experiments

[Andrew H Barclay]

The locations of four stations in the IRIS DMC's _OBSIP virtual network have been revised after transcription errors were found:

ZM:S6H27 (SE Indian Ridge, 2001-2).  Longitude corrected from 105.2543E to 115.2543E
7D:M04C (Cascadia Community Experiment, 2014).  Latitude corrected from 45.5584N to 47.5584N
YO:320 (ENAM Community Experiment, 2014).  Longitude corrected from -74.3714E to -72.3714E
XO:WD61 (Alaska Community Experiment, 2018).  Station longitude corrected from -156.5798E to -156.8683E. (Channel metadata were OK.)