pipeline of last commit is skipped if a commit in current set contains `[ci skip]
### Summary
please see https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/15772#note_51358613
I made few commits in a tiny time gap. one of these commit contained a `[ci skip]` but the ci is skipped for last commit also which doesn't had `[ci skip]`.
### Steps to reproduce
1. create a commit with `[ci skip]`
2. create one more commit without `[ci skip]`
3. push the commits
### What is the current *bug* behavior?
the ci is skipped.
### What is the expected *correct* behavior?
CI should run since last commit doesn't contains `[ci skip]`
/cc @rymai @grzesiek
issue