Switch default Docker version to 1.12.0
Switch default Docker version to 1.12.0

juliengk/os,SvenDowideit/os,gizmotronic/os,ibuildthecloud/os,rancher/os,rancher/os,juliengk/os,rancherio/os,rancherio/os,rancherio/os,SvenDowideit/os,ibuildthecloud/os,gizmotronic/os