Do premerge testing with Jenkins files from the PR
    
    Varibales for git checkout (WAIVERDB_GIT_REPO, WAIVERDB_GIT_BRANCH)
    were evaluated during openshift template applications. Which caused that
    PRs were tested with Jenkins file in master branch intead of PR ones.
    
    Openshift BuildConfig is not able to specify git refs to be fetched and
    PR refs are not available, to avoid this issue WAIVERDB_GIT_REF_COMMIT
    contains SHA of last PR (or can be master branch).