openstack-ansible-os_nova/tests at 597127e60c0a1aee20cba0ae7577936fc63268e6 - openstack-ansible-os_nova - OpenDev: Free Software Needs Free Tools

This patch adjusts the nova-lxd deployment so that it works correctly
with LXD3 and bionic.
* Update the zuul job and project config to switch from xenial to bionic.
* Change the variable lxd_storage_pool to always have a defined value
 in the role defaults. This variable represents the name of the LXD
 storage pool which is distinct from any names associated with underlying
 storage. LXD storage pools created with 'lxd init' are always called 'default'.
* Switch the role test storage backend from dir to ZFS. nova-lxd is
 currently not working for the dir backend as it expects the storage
 subsystem to support quotas.
* Due to limitiations in nova-lxd it is necessary to ensure that the
 LXD storage pool name and ZFS pool names are both set to 'default'.
Closes-Bug: #1800837
Change-Id: If1e48bb2e789e13f20435da19907b5adb7c1ef1f