Do not link disks when attaching during upgrade (#1889) (#1892)

By default, govc vm.disk.attach "links" disks, which sets their disk
mode to independent. Disable this flag to ensure attached disks are
dependent disks, so that snapshots can be taken.

(cherry picked from commit f87e94f)

installer/build/scripts/upgrade/upgrade.sh

@@ -388,10 +388,10 @@ function moveDisks {
 
   # TODO rename to new version
   echo "Attaching migrated disks to new VIC appliance"
-  govc vm.disk.attach -vm="$NEW_VM_NAME" -ds "$NEW_DATASTORE" -disk "$NEW_DATA_DISK" || (log "Failed to attach data disk" && exit 1)
+  govc vm.disk.attach -vm="$NEW_VM_NAME" -ds "$NEW_DATASTORE" -disk "$NEW_DATA_DISK" -link=false || (log "Failed to attach data disk" && exit 1)
   if [ "$ver" != "$VER_1_2_1" ]; then
-    govc vm.disk.attach -vm="$NEW_VM_NAME" -ds "$NEW_DATASTORE" -disk "$NEW_DB_DISK" || (log "Failed to attach database disk"  && exit 1)
-    govc vm.disk.attach -vm="$NEW_VM_NAME" -ds "$NEW_DATASTORE" -disk "$NEW_LOG_DISK" || (log "Failed to attach log disk" && exit 1)
+    govc vm.disk.attach -vm="$NEW_VM_NAME" -ds "$NEW_DATASTORE" -disk "$NEW_DB_DISK" -link=false || (log "Failed to attach database disk"  && exit 1)
+    govc vm.disk.attach -vm="$NEW_VM_NAME" -ds "$NEW_DATASTORE" -disk "$NEW_LOG_DISK" -link=false || (log "Failed to attach log disk" && exit 1)
   fi
   log "Finished attaching migrated disks to new VIC appliance"