s4-join: enable cleanup on failed join

if a join fails, then cleanup the old records

source4/scripting/python/samba/join.py

@@ -818,7 +818,7 @@ class dc_join(object):
             ctx.join_finalise()
         except Exception:
             print "Join failed - cleaning up"
-            #ctx.cleanup_old_join()
+            ctx.cleanup_old_join()
             raise