When use GerritChangeSource, the first test never work on step addStep(Gerrit(repourl=repo, mode="full",retry=[60,60],timeout=3600))...
The step launch a cloning of git repo

The build always fails with fatal: Remote branch refs/changes/xx/yy/zz not found in upstream origin...

Add check when clone to no add branch if the branch start with refs/changes/

Only this issue with > Git 1.8
See also http://trac.buildbot.net/ticket/2485#comment:8