CLOUDSTACK-2650 setting vm ip null in user_ip_address when static nat ip

Signed-off-by: Abhinandan Prateek <aprateek@apache.org>

engine/schema/src/com/cloud/network/dao/IPAddressDaoImpl.java

@@ -155,6 +155,7 @@ public class IPAddressDaoImpl extends GenericDaoBase<IPAddressVO, Long> implemen
         address.setAssociatedWithNetworkId(null);
         address.setVpcId(null);
         address.setSystem(false);
+        address.setVmIp(null);
         update(ipAddressId, address);
     }