The spice and vnc consoles are mutually exclusive with Horizon set
to auto-detect the console type. It is also clear from the
configuration method that the designed implementation is to deploy
only one of them.
This patch ensures that only one is enabled at a time by explicitly
disabling the vnc console (which defaults to enabled).
Change-Id: Ib0368d3d6125e4abe7f9a9c40748457fc0d349f2
113a4be0f2