Add DB index to Alert.last_sent column to speed up listAlertsCmd.
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/incubator-cloudstack
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/incubator-cloudstack
Fix a bug in listHosts that returns wrong zoneId for host.