jenkins job git-skara-jdk11u-fast-startup-incubator failing

Jenkins job[git-skara-jdk11u-fast-startup-incubator](https://ci.adoptopenjdk.net/view/Failing%20Temurin%20jobs/job/git-mirrors/job/adoptium/job/git-skara-jdk11u-fast-startup-incubator/) has been failing for long time

might require a cleanup/manual fix in workspace

Log:
```
+ git rebase skara/master master

It seems that there is already a rebase-apply directory, and
I wonder if you are in the middle of another rebase. If that is the
case, please try
git rebase (--continue | --abort | --skip)
If that is not the case, please
rm -fr "/home/jenkins/workspace/git-mirrors/adoptium/git-skara-jdk11u-fast-startup-incubator/workspace/jdk11u/.git/rebase-apply"
and run me again. I am stopping in case you still have something
valuable there.
Build step 'Execute shell' marked build as failure
```