static File getSystemAppsFile(Context context, int userId) {
        return new File(context.getFilesDir() + File.separator + "system_apps"
                + File.separator + "user" + userId + ".xml");
    }
Returns if this task should be run on OTA.
This is indicated by the presence of the system apps file.
engine/src/main/java/com/oasisfeng/island/provisioning/task/DeleteNonRequiredAppsTask.java