Fix broken UI for admin system hooks

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix header case

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'fix/system_hooks_ui' of /home/git/repositories/gitlab/gitlabhq