Avoid stub_gitlab_rb when testing git_data_dirs
Avoid stub_gitlab_rb when testing git_data_dirs

stub_gitlab_rb makes sure the data is a Mash.

git_data_dirs({}) when part of gitlab.rb does not do that, so the test
wasn't testing what it was intended to (it did not fail when reverting
542aea4aa4b37c50751e98a949eac4f2b52d57d8).

Here we bypass the use of our convenience helper in order to get an
accurate reproduction of the issue so we can test the fix in
542aea4aa4b37c50751e98a949eac4f2b52d57d8

gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab