
When set to its current value of 'None', no instances can be scheduled as no AZ matching that name exists in an installation with the default Availability Zones. The default AZ is 'nova', therefore, by default we should default `nova_default_schedule_zone` to the same value ensuring that the default values result in the ability to schedule instances. This is a fix to: I69627d7987a3158a3a005406245ea6df881715d8 and should solve the issues in AIO gating that were manifesting as: http://logs.openstack.org/06/293606/1/check/gate-openstack-ansible-dsvm-commit/603c28e/console.html#_2016-03-16_20_19_13_293 Change-Id: I0c4a78d922798f332f7a485d15f75b0cb8d74ac7