Ifa5f251fdfb8de737ad2ed96491d45294ce23a0c renamed the afs and afsdb
groups to afs-file-server and afs-db-server, but didn't update the
group files.
Previously the firewall rules were duplicated in the afs/afsdb group;
but now all afs servers are in the afs-server-common group. Rename
afs.yaml->afs-server-common.yaml and remove the now unnecessary
afsdb.yaml.
Remove one of the old group vars files and rename the other to
afs-server-common so we can restore the udp ports they open in our
firewall rules.
Change-Id: I17dd0596660addf061ade31b4450bf040c01ffe8
6d0c4b0b3b