Update upgrade guide if you have more than one backup .tar file

doc/update/6.4-to-6.5.md

@@ -65,7 +65,7 @@ To make sure you didn't miss anything run a more thorough check with:
 
     sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production
 
-If all items are green, then congratulations upgrade complete!
+If all items are green, then congratulations upgrade is complete!
 
 ## Things went south? Revert to previous version (6.4)
 
@@ -79,3 +79,4 @@ Follow the [`upgrade guide from 6.3 to 6.4`](6.3-to-6.4.md), except for the data
 cd /home/git/gitlab
 sudo -u git -H bundle exec rake gitlab:backup:restore RAILS_ENV=production
 ```
+If you have more than one backup *.tar file(s) please add `BACKUP=timestamp_of_backup` to the command above.
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