use ~git instead of /home/git, as the home directory of git could be any where

#5987, update on this PR

There are probably other places we may want to set the home variable in the config file, and then use this variable instead. This probably requires further discussion

You can check my doc in https://gitlab.com/gitlab-org/gitlab-recipes/merge_requests/1

The init.d issue as is on another MR at https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4, see the discussion there