Fix diskimage-builder cherry-pick
Fix diskimage-builder cherry-pick

Forgot to commit this before I pushed.

dpkshetty/instack-undercloud,bcrochet/instack-undercloud,eprasad/instack-undercloud,rdo-management/instack-undercloud,bcrochet/instack-undercloud,agroup/instack-undercloud,dmsimard/instack-undercloud,dpkshetty/instack-undercloud,agroup/instack-undercloud,eprasad/instack-undercloud,rdo-management/instack-undercloud,dmsimard/instack-undercloud