Update GitLab version to 7.5.2_omnibus.5.2.1.ci-1

    Also stop nginx before upgrade. This is needed when upgrading from 7.3.0 so
it was added as an safety measure. It would be better to test for the installed
version. Maybe later.

https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/doc/update.md
Add ability to customize SSL port
Add ssl tag to task so gitlab.rb is updated when SSL cert parameters change
Use new LDAP configuration syntax in gitlab.rb

A few new parameters were added, so new variables for those were created.
Update RPM download URL

Change '6.5' to '6.6' in the download URL.
Bump version number to 1.2.2
Merge branch 'release/1.2.2'
Merge tag '1.2.2' into develop

1.2.2