Updated https root to match installation manual; some other minor changes

Fixes https root to go into /home/git/gitlab/public, otherwise attachments will show 404.

Updated rewrite rule, so it won't point to someone else's install of GitLab.

There is [no option TLSv2 for ssl_protocols in nginx](http://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_protocols), updated to fix error. 

Match config to http version.