Workaround for Jenkins issue

*steps to reproduce*:
it failed only when set
withMerge policy

``
try {
    stage(“Checkout”) {
       gerrit.gerritPatchsetCheckout([
           credentialsId: CREDENTIALS_ID,
           *withMerge: true*,
       ])
}``

proofs: https://ci.mcp.mirantis.net/view/MAP/job/map-build-component-image/5/console

root cause - incorrect case-resolving in git plugin
related issue: https://issues.jenkins-ci.org/browse/JENKINS-51638
p.s. workaround in comments

Change-Id: I9ffd85a61613eecaeb96fbacb1a28bb6a37cb60f
1 file changed