minor updates & formatting changes

minor updates @ formatting changes to match other versions of file.
Unify formatting of
https://github.com/gitlabhq/gitlabhq/blob/master/lib/support/nginx/gitlab,
https://github.com/gitlabhq/gitlabhq/blob/master/lib/support/nginx/gitlab-ssl,
&
https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/files/gitlab-cookbooks/gitlab/templates/default/nginx-gitlab-http.conf.erb
Merge pull request #8273 from bbodenmiller/nginx-updates

Nginx updates