Release version 1.2.0

Minor feature release which adds ZooKeeper server security support.

• Set distribution_version correctly when distribution changes ( Issues: #57 #67 )
• Preserve ${user} in hadoop.tmp.dir ( Issues: #59 #66 )
• Update test-kitchen support ( Issues: #68 )
• Only allow supported distributions ( Issues: #71 )
• Create local directories for MRv1 ( Issues: #72 )
• ZooKeeper security ( Issues: #74 )
• Rubocop cleanups ( Issues: #75 )