apps-menu: Handle non-UTF8 filename encodings more gracefully

Instead of failing completely if any .desktop file uses a filename
encoding other than UTF-8, just filter out the offending apps.

https://bugzilla.gnome.org/show_bug.cgi?id=651503

extensions/apps-menu/extension.js

@@ -393,7 +393,13 @@ const ApplicationsButton = new Lang.Class({
             if (nextType == GMenu.TreeItemType.ENTRY) {
                 let entry = iter.get_entry();
                 let appInfo = entry.get_app_info();
-                let app = appSys.lookup_app(entry.get_desktop_file_id());
+                let id;
+                try {
+                    id = appInfo.get_id(); // catch non-UTF8 filenames
+                } catch(e) {
+                    continue;
+                }
+                let app = appSys.lookup_app(id);
                 if (appInfo.should_show()) {
                     let menu_id = dir.get_menu_id();
                     this.applicationsByCategory[categoryId].push(app);