Request nginx restart after creating the nginx config file.

We should notify nginx service after creating the nginx config file.
This is necessary for nginx to apply the new created config file.

Without this, we need to manually (reload/restart) the nginx service after running
gitlab puppet module. (not desirable behaviour.)

This commit fix this problem making nginx config file notify the nginx service.
because of this puppet will restart nginx, making possible to access the gitlab
url correctly after the gitlab puppet module execution.