remove auto-execution of gitlab:setup

[LongLiveCHIEF]

This code block was valid in older versions of gitlab, but in 10.x versions, there are several situations where you would be managing the gitlab service and had configurations in the postgresql hash, and have postgresql disabled, or merely not indicate and let the default psql config for the enable setting be utilized by omnibus chef. (for example, gitlab HA configurations for database roles/nodes, or when providing your own psql database)

Additionally, the git_data_dir is no longer a valid param, and the postgres configuration doesn't use teh setup.complete file at this path any more. This causes gitlab to re-perform setup on each puppet run if you have postgres configurations but don't explictly indicate enable => true

Fixes #35
Fixes #195

[bastelfreak]

Thanks @LongLiveCHIEF ! Can you please create feature branches in a fork, and not in the org repo?