Fix error when building without CI_COMMIT_REF_NAME set
The current version of master cannot be built without that variable set due to an error that occurs right as the build starts.
...
2: from /root/omnibus-gitlab/lib/gitlab/build/check.rb:12:in `is_ee?'
1: from /root/omnibus-gitlab/lib/gitlab/build/check.rb:20:in `is_auto_deploy?'
/root/omnibus-gitlab/lib/gitlab/build/check.rb:28:in `is_auto_deploy_branch?': undefined method `include?' for nil:NilClass (NoMethodError)
As a temporary workaround, you can also set export CI_COMMIT_REF_NAME=""
which seems to work fine.