Make $type argument of function hosting_available_tasks() optional.

Patch attached.

The function now looks like this:

/**
 * User-driven task descriptions
 *
 * This is the list of tasks that can be invoked by the user. This doesn't
 * check permissions or relevance of the tasks.
 *
 * Modules can extend this list using hook_hosting_tasks()
 *
 * @see hook_hosting_tasks()
 * @see hosting_task_menu_access()
 */
function hosting_available_tasks($type = NULL, $reset = FALSE) {
  static $cache = array();

  if (!sizeof($cache) || $reset) {
    $cache = module_invoke_all('hosting_tasks');
    drupal_alter('hosting_tasks', $cache);
  }
  if ($type){
    return $cache[$type];
  }
  else {
    return $cache;
  }