Pin & unpin a previous commit stops further builds when using Redis

[liuhx1027]

reproduce steps:

1. setup a pipeline with git-multi-branch-resource + redis
2. push some commits / branches to make it run for 3-5 times.
3. pin one previous commits and manually trigger the task which monitors the resource in the pipeline.
4. unpin the previous commits
5. create a new branch, make some changes, commit it, push it.
6. the pipeline would not be triggered by the new commit.

any thought would be appreciated!