Enhanced p4_vars.template to support operating on an SDP-managed
host where no p4d process runs, such as a p4p (proxy) host, where
no /p4/n/root/server.id file exists. The $SERVERID value will
be empty (but defined) in this case.
Enhanced to better support operating with replicas that share
/depotdata with their master servers, by making P4TRUST and
P4TICKETS values contain $SERVERID.
Moved SHAREDDATA from p4_vars to instance_vars, since it is not
inherently a global setting. In sophisticated enterprise
environments, it can vary on a per-replica basis. Adjusted