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

tests/end_to_end/scenarios/simple_channel_join_fixed.py

@@ -3,7 +3,7 @@ from scenarios import *
 conf = "fixed_server"
 
 scenario = (
-    send_stanza("<presence from='{jid_one}/{resource_one}' to='#foo@{biboumi_host}/{nick_one}' />"),
+    send_stanza("<presence from='{jid_one}/{resource_one}' to='#foo@{biboumi_host}/{nick_one}' ><x xmlns='http://jabber.org/protocol/muc'/></presence>"),
     sequences.connection("irc.localhost", '{jid_one}/{resource_one}', fixed_irc_server=True),
     expect_stanza("/message/body[text()='Mode #foo [+nt] by {irc_host_one}']"),
     expect_stanza("/presence[@to='{jid_one}/{resource_one}'][@from='#foo@{biboumi_host}/{nick_one}']/muc_user:x/muc_user:item[@affiliation='admin'][@role='moderator']",