Use clutter_event_get_* instead of ShellGlobal

Before Clutter gained accessors for event information, we had
shell_global_ functions.  Now that Clutter has them, use them and
delete the ShellGlobal code.

http://bugzilla.gnome.org/show_bug.cgi?id=594561

js/ui/dash.js

@@ -641,7 +641,7 @@ Dash.prototype = {
         }));
         this._searchEntry.entry.connect('key-press-event', Lang.bind(this, function (se, e) {
             let text = this._searchEntry.getText();
-            let symbol = Shell.get_event_key_symbol(e);
+            let symbol = e.get_key_symbol();
             if (symbol == Clutter.Escape) {
                 // Escape will keep clearing things back to the desktop.
                 // If we are showing a particular section of search, go back to all sections.