Confirm if Git data directory needs specific permissions and ownership

For quite a long period of time, we have been managing the git data directory (default /var/opt/gitlab/git-data) and the repositories storage directories (default /var/opt/gitlab/git-data/repositories) to have specific ownership and permissions. For this specific reason, git_data_dirs pointed at the git data directory, and gitaly['configuration']['storage'] pointed at the repositories storages.

But basic inspection seems to indicate that the former is not actually required - we should only care about the repositories storage directories having necessary ownership and permissions. It doesn't matter if the parents/ancestors of that path doesn't share the same permission/ownership. We need to confirm this, and get rid of the piece of code that handles the git data directory.