[ Sent upstream: https://gitlab.com/gitlab-org/gitlab-shell/merge_requests/40

  This was filed upstream but decided the better way to go is to
  configure default git templates to be just empty.

  Until we implement that, we continue to carry this patch as NXD ]

gitlab-shell uses completely own whole set of git hooks and just
symlinks repo.git/hooks to path/to/gitlab-shell/hooks/.

Original hooks that git added there - when initializing repository -
from its template, and which are by default deactivated, are currently
moved to repos.git/hooks.old.<timestamp>, e.g.

$ ls -F nexedi/helloweb.git/
    config
    description
    HEAD
    hooks@                  -->  ...path/to/gitlab-shell/hooks/
    hooks.old.1446564288/
    info/
    packed-refs
    refs/

$ ls -F nexedi/helloweb.git/hooks.old.1446564288/
    applypatch-msg.sample*
    post-update.sample*
    pre-commit.sample*
    pre-push.sample*
    update.sample*
    commit-msg.sample*
    pre-a...