Move code for faking up an OpenAFS configuration directory into its
own "common" directory, as it's going to be of use to more tests than
just those in auth.
Change-Id: I9c80dd66763e222deca98bc7744ff317111c6ed8
Reviewed-on: http://gerrit.openafs.org/4806
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
