Server Upgrade: Update entries in order specified in file

Dictionary replaced with list. Particular upgrades are
executed in the same order as they are specified in update
a file.

Different updates for the smae cn, are not merged into one upgrade

https://fedorahosted.org/freeipa/ticket/4904

Reviewed-By: David Kupka <dkupka@redhat.com>

ipaserver/install/plugins/update_uniqueness.py

@@ -218,7 +218,7 @@ class update_uniqueness_plugins_to_new_syntax(PreUpdate):
                                   "plugin %s (%s)",
                                   entry.dn, e)
 
-            update_list.append({entry.dn: update})
+            update_list.append(update)
 
         return False, True, update_list