Set gpfs4 group membership for users in GPFS4 to facilitate proper routing for ssh, ood and job submission

Add all users who are on GPFS4 to gpfs4 group before we make changes to application proxies to provide reliable routing when users are in one of three-states to distinguish between:

1. GPFS4 users
2. GPFS5 users
3. Lookup failures (which should deny login rather than default to GPFS4)