tree fc51fb13d312e6bf4b61cd60fb6378b8253f3df6
parent 063672f8d3cf22bb90cff5bb9144b7f5d0fc029f
author James E. Blair <jeblair@hp.com> 1419963149 -0800
committer James E. Blair <jeblair@hp.com> 1423073263 -0800

Support cross-repo-dependencies in dependent pipelines

Parse commit messages for "Depends-On: <changeid>" and treat
matching changes as changes that the given change depends on.

This will treat any changes in any branch of any project as
such.  If the projects share a dependent change queue, the
changes will be enqueued in order.  If they do not share a
change queue in a dependent pipeline, then the latter one will
be unable to be enqueued until the change it depends on merges.

If the dependencies result in a cycle, Zuul will log the error
but otherwise the problematic changes will be ignored.

Dependent changes in independent pipelines are not yet addressed.

Change-Id: I90c173f86d11e6c44d1f408646589b7c75b1cd52