Fix leftovers from the original nginx vhost templtae used by GitLab

Fixed logs filenames of the Gitlab CI vhost on port 80 which was using the values from the GitLab vhost (gitlab_access.log intead of gitlab_ci_access.log).
Updated a few comments that refered to "gitlab" instead of "gitlab_ci"
Merge pull request #9 from vivienlacourba/patch-1

Fix leftovers in GitLab CI nginx template coming from the original GitLab template