prevent publisher on mentions and tags from crashing

public/javascripts/pages/mentions-index.js

@@ -2,6 +2,8 @@ Diaspora.Pages.MentionsIndex = function() {
   var self = this;
 
   this.subscribe("page/ready", function(evt, document) {
+
+    self.aspectNavigation = self.instantiate("AspectNavigation", document.find("ul#aspect_nav"));
     self.stream = self.instantiate("Stream", document.find("#aspect_stream_container"));
     self.infiniteScroll = self.instantiate("InfiniteScroll");
   });

public/javascripts/pages/tag-followings-index.js

@@ -2,6 +2,7 @@ Diaspora.Pages.TagFollowingsIndex = function() {
   var self = this;
 
   this.subscribe("page/ready", function(evt, document) {
+    self.aspectNavigation = self.instantiate("AspectNavigation", document.find("ul#aspect_nav"));
     self.stream = self.instantiate("Stream", document.find("#aspect_stream_container"));
     self.infiniteScroll = self.instantiate("InfiniteScroll");
   });