xmpp: disable HTTPS for BOSH

It's not exposed, we proxy from the web frontend.

prosody/Dockerfile

@@ -9,7 +9,7 @@ RUN \
 
 COPY rootfs/ /
 
-EXPOSE 5222 5269 5347 5280 5281
+EXPOSE 5222 5269 5347 5280
 
 VOLUME /config
 

prosody/rootfs/defaults/prosody.cfg.lua

@@ -72,6 +72,8 @@ modules_enabled = {
 		--"legacyauth"; -- Legacy authentication. Only used by some old clients and bots.
 };
 
+https_ports = { }
+
 -- These modules are auto-loaded, but should you want
 -- to disable them then uncomment them here:
 modules_disabled = {