[OpenAFS] Distro vs. @sys. Round 1: FIGHT!

[Jeff Blaine]

RHEL 5 vs. RHEL 6

Both have the same @sys currently.

Due to drastic differences in OS libraries present, those (like us),
who use @sys in PATH, get bitten. That is, our build of AppX for
'amd64_linux26' that was built on RHEL 5 will not work on RHEL 6,
and we need to support both.

We had trouble with this once in the past. We solved it by
forcing the newer machines to set a custom sysname in afs.rc (like
amd64_linux26_v2).

Any other options, or is the standard thing everyone does?