fixed syntax error

EXTRAS/example-configurations/conf.d/41-s2s.yml

@@ -1,7 +1,5 @@
-# starttls is gloablly required for s2s 
-max_stanza_size: 131072
-
- -
+listen:
+  -
     port: 5269
     ip: "::"
     module: ejabberd_s2s_in