a11y: Setting role and label-actor for runDialog

https://bugzilla.gnome.org/show_bug.cgi?id=670308

js/ui/runDialog.js

@@ -209,6 +209,8 @@ const RunDialog = new Lang.Class({
         let entry = new St.Entry({ style_class: 'run-dialog-entry' });
         ShellEntry.addContextMenu(entry);
 
+        entry.label_actor = label;
+
         this._entryText = entry.clutter_text;
         this.contentLayout.add(entry, { y_align: St.Align.START });
         this.setInitialKeyFocus(this._entryText);