#4378: Remove last host from excludes list

Author: ustcweizhou

server/src/main/java/com/cloud/vm/UserVmManagerImpl.java

@@ -5632,14 +5632,12 @@ public VirtualMachine migrateVirtualMachine(Long vmId, Host destinationHost) thr
 
         DeployDestination dest = null;
         if (destinationHost == null) {
+            vm.setLastHostId(null); // Last host does not have higher priority in vm migration
             final VirtualMachineProfile profile = new VirtualMachineProfileImpl(vm);
             final Host host = _hostDao.findById(srcHostId);
             final DataCenterDeployment plan = new DataCenterDeployment(host.getDataCenterId(), host.getPodId(), host.getClusterId(), null, null, null);
             ExcludeList excludes = new ExcludeList();
             excludes.addHost(srcHostId);
-            if (vm.getLastHostId() != null && vm.getLastHostId() != srcHostId) {
-                excludes.addHost(vm.getLastHostId());
-            }
             try {
                 dest = _planningMgr.planDeployment(profile, plan, excludes, null);
             } catch (final AffinityConflictException e2) {