afs: Log a message on invalid FetchStatus receipt

afs: Log a message on invalid FetchStatus receipt

If we get an invalid AFSFetchStatus structure from a server, log a
message to indicate as such. This serves as a warning to urge people
to fix their fileservers, and to explain what is doing.

Reviewed-on: http://gerrit.openafs.org/6881
Reviewed-by: Alistair Ferguson <alistair.ferguson@mac.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 577d5d99fefb62f0b52a568207d2352946b36137)

Change-Id: I10dc2dd94d2cd7277e48dfff1accb36e7cab8537
Reviewed-on: http://gerrit.openafs.org/7993
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>