MB-8651,2:  add support for 220 builders on ubuntu-12 and centos-6

Change-Id: I6af32c48ee1d82ca64c23dbe35d46dd3683a130e
Merge branch 'master' of https://github.com/couchbase/build

* 'master' of https://github.com/couchbase/build:
  Fix bug for auto-staging, auto-releasing and auto-undo
  Make auto staging releasing and undo support for MAC