[Buildbot] #2875: support retryOnFailure

[Buildbot trac]

#2875: support retryOnFailure
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Reporter:  dustin       |      Owner:
    Type:  enhancement  |     Status:  new
Priority:  major        |  Milestone:  0.9.0
 Version:  0.8.9        |   Keywords:
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 The metabuildbot's virtualenv step often fails on certain buildslaves.  In
 fact, it's never useful information when that step fails.

 It would be great if failures in that step were automatically retried.

 But there's no way to indicate that a step's failure should be turned into
 a RETRY status for the build (flunkOnFailure turns it into FAILURE, but
 not RETRY).

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Ticket URL: <http://trac.buildbot.net/ticket/2875>
Buildbot <http://buildbot.net/>
Buildbot: build/test automation