mod_component: Send <?xml on initial stream (thanks xnyhps)

plugins/mod_component.lua

@@ -158,6 +158,7 @@ function stream_callbacks.streamopened(session, attr)
 	session.streamid = uuid_gen();
 	session.notopen = nil;
 	-- Return stream header
+	session.send("<?xml version='1.0'?>");
 	session.send(st.stanza("stream:stream", { xmlns=xmlns_component,
 			["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=session.host }):top_tag());
 end