Do not set perms on an AFS repository path.

If using OpenAFS to store gitlab repositories, i.e. the repository
path begins with "/afs/.../", the attempted chowns in the gitlab
shell recipe will fail due to some AFS weirdness.
Since AFS does not use Unix permissions and occasionally doesn't
play nicely with them, the simple solution is to prevent gitlab
(or rather chef) from attempting to set ownership and *just*
create the directory.

This means it will be the sysadmin's reponsibility to make sure
whatever AFS principal gitlab is running under has the permissions
to read and write the repository path. This seems reasonable to
me since making gitlab run with a set of AFS/Kerberos permissions
requires some minor modifications anyway.

This change allows gitlab-ctl reconfigure to keep running if
the repositories are being stored in AFS (otherwise, it fails
due to an internal error when attempting to chown).