And modify the tests to work, by adding the <x/> node in all join presences

tests/end_to_end/scenarios/simple_channel_join.py

@@ -12,7 +12,7 @@ def expect_self_join_presence(jid, chan, nick, irc_server="{irc_server_one}"):
 
 
 scenario = (
-    send_stanza("<presence from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}/{nick_one}' />"),
+    send_stanza("<presence from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}/{nick_one}' ><x xmlns='http://jabber.org/protocol/muc'/></presence>"),
     sequences.connection(),
 
     expect_self_join_presence(jid = '{jid_one}/{resource_one}', chan = "#foo", nick = "{nick_one}"),