Most build failures are unrelated to the push revision

[evgenyrp]

Marco:

It might also be because we'd only need to analyze the failure on the actual push where the failure started
so you'd need to change the pulse listener to not only deduplicate, but also look at when the failure first started
load the revision, check the parent revision, check if the build was already failing in the parent revision
and loop until you find the first revision where the build was not failing

We should investigate how to allow the build repair agent to do that. For now, I'm disabling notifications if there's no patch.