Use a ? after the $request_uri to perform a valid Redirect while cloning.

fixes #6203

before:

❯ curl -I http://gitlab/namespace/repo.git/info/refs?service=git-upload-pack
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Sat, 26 Jul 2014 18:20:27 GMT
Content-Type: text/html
Content-Length: 178
Connection: keep-alive
Location: https://gitlab/namespace/repo.git/info/refs?service=git-upload-pack?service=git-upload-pack

after:

❯ curl -I http://gitlab/namespace/repo.git/info/refs\?service=git-upload-pack
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Sat, 26 Jul 2014 18:23:54 GMT
Content-Type: text/html
Content-Length: 178
Connection: keep-alive
Location: https://gitlab/namespace/repo.git/info/refs?service=git-upload-pack

[ci skip]
Merge pull request #7378 from jojosch/nginx-ssl-redirect

Use a ? after the $request_uri to perform a valid Redirect while cloning...