[Buildbot] #3457: Test all supported versions of MySQL, postgres in metabuildbot

[Buildbot trac]

#3457: Test all supported versions of MySQL, postgres in metabuildbot
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Reporter:  dustin  |       Owner:  dustin
    Type:  task    |      Status:  new
Priority:  minor   |   Milestone:  ongoing
 Version:  0.8.12  |  Resolution:
Keywords:          |
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Comment (by dustin):

 We should also document supported versions.

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Ticket URL: <http://trac.buildbot.net/ticket/3457#comment:1>
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Buildbot: build/test automation