fix caching in get_ipa_config

Different opbject types were compared thus always result of comparation
was False and caching does not work.

https://fedorahosted.org/freeipa/ticket/5463

Reviewed-By: Jan Cholasta <jcholast@redhat.com>

ipaserver/plugins/ldap2.py

@@ -208,7 +208,7 @@ class ldap2(CrudBackend, LDAPClient):
 
         try:
             config_entry = getattr(context, 'config_entry')
-            if config_entry.conn is self.conn:
+            if config_entry.conn.conn is self.conn:
                 return config_entry
         except AttributeError:
             # Not in our context yet