(PE-2456) Add proper 3.1 master auth.conf hash

The custom_auth_conf fact had an incorrect hash for a 3.1 master (also
incorrectly labeled as being for a 3.0 master). This commit adds the
proper hash, though it preserves the old hash because it's not clear
where it came from or whether it actually may occur in some cases...
Merge pull request #27 from nicklewis/PE-2456-add-3.1-master-hash

(PE-2456) Add proper 3.1 master auth.conf hash