Bug 790355 - install ipmitools packages on centos6 builders. r=dustin

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extra : rebase_source : 5dc43bac96004a67a410ae26343e0a272ef75c13
Backed out changeset 584c93614019 for bustage
Bug 823661: add the mysql client on hosts running dbcron; r=armenzg
Bug 790355 - install ipmitools packages on centos6 builders. r=dustin

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extra : rebase_source : 7ac5005c24684be3bc1b4445d27ea27dabc51046
Bug 823686: add /etc/aliases with root pointing to releng-shared; r=kmoir, r=rail