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

tests/end_to_end/scenarios/multiline_message.py

@@ -34,7 +34,7 @@ scenario = (
     # joining the room with the new user.
     sleep_for(0.2),
     # Second user joins
-    send_stanza("<presence from='{jid_two}/{resource_one}' to='#foo%{irc_server_one}/{nick_two}' />"),
+    send_stanza("<presence from='{jid_two}/{resource_one}' to='#foo%{irc_server_one}/{nick_two}' ><x xmlns='http://jabber.org/protocol/muc'/></presence>"),
     sequences.connection("irc.localhost", '{jid_two}/{resource_one}'),
     # Our presence, sent to the other user
     expect_unordered(