ShellApp+ShellGlobal: unify app launch context code

Extend shell_global_create_app_launch_context() with the required
parameters and use that for shell_app_launch() too.

https://bugzilla.gnome.org/show_bug.cgi?id=669603

js/ui/components/autorunManager.js

@@ -64,7 +64,7 @@ function startAppForMount(app, mount) {
 
     try {
         retval = app.launch(files, 
-                            global.create_app_launch_context())
+                            global.create_app_launch_context(0, -1))
     } catch (e) {
         log('Unable to launch the application ' + app.get_name()
             + ': ' + e.toString());