FIX: Private messages were getting the `has-category` style

app/assets/javascripts/discourse/controllers/header.js.es6

@@ -10,6 +10,11 @@ export default DiscourseController.extend({
   loginRequired: Em.computed.alias('controllers.application.loginRequired'),
   canSignUp: Em.computed.alias('controllers.application.canSignUp'),
 
+  hasCategory: function() {
+    var cat = this.get('topic.category');
+    return cat && !cat.get('isUncategorizedCategory');
+  }.property('topic.category'),
+
   showPrivateMessageGlyph: function() {
     return !this.get('topic.is_warning') && this.get('topic.isPrivateMessage');
   }.property('topic.is_warning', 'topic.isPrivateMessage'),

app/assets/javascripts/discourse/templates/header.hbs

@@ -94,7 +94,7 @@
 
     {{#if showExtraInfo}}
       <div class="extra-info-wrapper">
-        <div {{bind-attr class=":extra-info topic.category.isUncategorizedCategory::has-category"}}>
+        <div {{bind-attr class=":extra-info hasCategory"}}>
           {{#if showStarButton}}
             <a {{bind-attr class=":star topic.starred:starred"}} {{action "toggleStar"}} href='#' {{bind-attr title="topic.starTooltip"}}></a>
           {{/if}}