declare namespace in relevant plugin

src/converse-core.js

@@ -1615,12 +1615,9 @@
                  *
                  * See: http://xmpp.org/extensions/xep-0030.html#info
                  */
-                // FIXME: should go into MUC
-                converse.connection.disco.addFeature('jabber:x:conference');
                 converse.connection.disco.addFeature(Strophe.NS.BOSH);
                 converse.connection.disco.addFeature(Strophe.NS.CHATSTATES);
                 converse.connection.disco.addFeature(Strophe.NS.DISCO_INFO);
-                // FIXME: should go into Roster view plugin?
                 converse.connection.disco.addFeature(Strophe.NS.ROSTERX); // Limited support
                 if (converse.use_vcards) {
                     converse.connection.disco.addFeature(Strophe.NS.VCARD);

src/converse-muc.js

@@ -66,6 +66,7 @@
             Features: {
                 addClientFeatures: function () {
                     this._super.addClientFeatures.apply(this, arguments);
+                    converse.connection.disco.addFeature('jabber:x:conference'); // Invites
                     if (this.allow_muc) {
                         this.connection.disco.addFeature(Strophe.NS.MUC);
                     }