Merge release branch 4.9 to master

* 4.9:
  CLOUDSTACK-9410: Data Disk shown as detached in XS

plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/resource/XenServerStorageProcessor.java

@@ -461,9 +461,6 @@ public class XenServerStorageProcessor implements StorageProcessor {
                     vbd.destroy(conn);
                 }
 
-                // Update the VDI's label to be "detached"
-                vdi.setNameLabel(conn, "detached");
-
                 hypervisorResource.umount(conn, vdi);
             }