buildbot/buildbot — pull request #273 by maruel (2011-10-24 23:53:32+00:00)
Title: Change SourceStamp.canBeMergedWith to behave like described in the doc.

docs/manual/cfg-builders.rst says 'Source stamps are compatible if: neither
source stamp has a patch (e.g., from a try scheduler)' but it wasn't the case.
Two SourceStamp could be merged if both had a change associated.