Comment 9 for bug 1378904

After renaming availability zones via horizon the live migrate option for instances in horizon does not work unless a host is specified. This is due to the AvailibilityZone filter which removes all hosts because the availibility_zone of the host is obtained from the RequestSpec object which is stored in the request_specs table in the nova_api database. When availability_zone is renamed it is not updated in this table hence the mismatch. Not sure if we need to file another bug for this.