Pass ChangeControl into CodeReviewCommit error instances

Within MergeOp these are keyed by Change.Id, but some error handling
code only receives the CodeReviewCommit and not the ID. That code is
reasonable in assuming there is a change/notes/control available, so
ensure this is the case when creating error instances.

Bug: issue 2911
Change-Id: If65398652f0e5b1a2b10a2fadc9a3b74bce7d556
2 files changed