Re-create nginx.conf during reconfigure

Closes https://gitlab.com/gitlab-org/gitlab-development-kit/merge_requests/286

mentioned in merge request !286 (closed)

@jacobvosmaer-gitlab LGTM MWPSed.

enabled an automatic merge when the pipeline for 83d08d04 succeeds

Just for the reference these are other *example files in GDK

grzesiek@debian: gdk $ find ./ -maxdepth 3 -name '*example'
./license-app/config/database.yml.example
./grafana/grafana.ini.example
./database.yml.example
./gitlab/config/resque.yml.example
./gitlab/config/gitlab.yml.example
./gitlab/config/unicorn.rb.example
./gitlab/config/secrets.yml.example
./gitlab/config/aws.yml.example
./gitlab/config/sidekiq.yml.example
./openssh/sshd_config.example
./Procfile.example
./nginx/conf/nginx.conf.example
./gitlab-shell/config.yml.example
./influxdb/influxdb.conf.example
./redis/resque.yml.example
./redis/redis.conf.example

Should we add something else to the clean-config?

merged

mentioned in commit 8e123b62

All of those should probably be in clean-config.