Changed CFG to P4BROKERCFG and moved it to the p4broker init script.
Changed get_pids to look for P4BROKERCFG rather than P4BROKERBIN so
that it only kills the broker instances running the config specified
by the init script.
This change makes it easy to just copy the p4broker_instance_init script
and change the config file name to be able to run more than one broker
per instance of Perforce. Useful to have one ssl and one non ssl broker.