github/codereview: Link commits to review issues
github/codereview: Link commits to review issues

Every time a commit is posted for review, a commit comment is added via
GitHub API that contains a link to the associated review issue. This
makes it possible to navigate from the commit back to the associated
review issue.

Change-Id: 1a60824a1f
Story-Id: SF-205

salsaflow/salsaflow,salsaflow/salsaflow