Issue

Context

• Gitlab plugin version: 1.5.2
• Gitlab version: 10.2.2
• Jenkins version: 2.73.3
• Job type: Freestyle

Problem description

When a build is triggered by a tag push event, the CI job branch name that appears in Gitlab CI is wrong:

I would expect refs/tags/<tag-name> to be <tag-name>.

This has two consequences:

• it conflicts with Gitlab CI native behavior: for a tagged commit, CI jobs use the tag name as job branch name:
  
• when you click the title, it should take you to <gitlab-url>/<repo-path>/commits/<tag-name>, but it actually takes you to <gitlab-url>/<repo-path>/commits/refs/tags/<tag-name>, which returns a 404.

Edit: here is an even better example: