Do not add image for empty avatar URL

issue10868
review367701002
(grafted from f9b71289bf696b369fd5c99cd1313202d1deffc0)

--HG--
branch : 6.0

src/sao.js

@@ -681,30 +681,28 @@ var Sao = {};
     };
 
     Sao.user_menu = function(preferences) {
-        var avatar_url = preferences.avatar_url || '';
-        if (avatar_url) {
-            avatar_url += '?s=30';
-        }
-        var avatar_badge_url = preferences.avatar_badge_url || '';
-        if (avatar_badge_url){
-            avatar_badge_url += '?s=15';
-        }
         jQuery('#user-preferences').empty();
         jQuery('#user-favorites').empty();
-        jQuery('#user-preferences').append(jQuery('<a/>', {
+        var user = jQuery('<a/>', {
             'href': '#',
             'title': preferences.status_bar,
         }).click(function(evt) {
             evt.preventDefault();
             Sao.preferences();
-        }).text(preferences.status_bar)
-            .prepend(jQuery('<img/>', {
-                'src': avatar_badge_url,
+        }).text(preferences.status_bar);
+        jQuery('#user-preferences').append(user);
+        if (preferences.avatar_badge_url) {
+            user.prepend(jQuery('<img/>', {
+                'src': preferences.avatar_badge_url + '?s=15',
                 'class': 'img-circle img-badge',
-            })).prepend(jQuery('<img/>', {
-                'src': avatar_url,
+            }));
+        }
+        if (preferences.avatar_url) {
+            user.prepend(jQuery('<img/>', {
+                'src': preferences.avatar_url + '?s=30',
                 'class': 'img-circle',
-            })));
+            }));
+        }
         var title = Sao.i18n.gettext("Logout");
         jQuery('#user-logout > a')
             .attr('title', title)