BOX:VOLUME pair should not contain hostname

In GETENV^ZOSVGUX (which is saved as GETENV^%ZOSV on GT.M/Unix systems), the the third piece and the second part of the fourth piece of the return value is determined by executing "hostname -s". For example, if the machine's hostname was "localhost", GETENV might return "OPEN^OPEN^localhost^OPEN:localhost".

The fourth piece, the BOX:VOLUME pair, is used by Taskman to determine the current BOX:VOLUME pair. There are two disadvantages to having the hostname of the machine included in the BOX:VOLUME pair. First, every time you move an OpenVista instance to a system with a different hostname, you must update the TASKMAN SITE PARAMETERS file. Second, in a failover cluster environment, you have to either: arrange for this configuration to be updated when failing over, have two sets of Taskman/RPC broker configuration, or name your cluster nodes with the same hostname.

On Cache systems, the second part of the BOX:VOLUME pair is determined by a call to $ZU(86), which returns (in the second *-separated piece) the name of the current Cache configuration. Since we do not have an equivalent configuration on GT.M systems, the next best thing is to hard-code it to a known value such as "GTM".

This change would mean that there is now effectively only one set of TASKMAN SITE PARAMETERS. The same set of parameters would take effect regardless of what host OpenVista is running on. This works well for us in practice, since we don't run more than one instance of Taskman at a time (in fact, we don't run any OpenVista processes on more than one machine at a time). However, the change may break backward compatibility.