Add disk size to flavors used by tempest tests
Add disk size to flavors used by tempest tests

Since [1], nova does not accept to create non-volume instances with
flavors with disk size to 0 so tempest tests fail.

This patch is creating disks with size 2GB to all flavors used by
tempest. cirros image is used in these tests so it should be fine.

[1] https://review.openstack.org/#/c/603910/

Change-Id: Ica694dee7ec0b9a5a7a1f998f50be4f339a42f5c

openstack/puppet-openstack-integration,openstack/puppet-openstack-integration,openstack/puppet-openstack-integration