queue/subqueue access checks could use drupal_alter

Whenever I deal with sites requiring more granular access than per-role, I struggle with some modules not allowing more granular access. Check #309007: Add drupal_alter() after hook_node_access_records() to see that this is a real problem and Drupal 7 is adding drupal_alter to node access records.

What I would like to have in nodequeue - to be able to control who has access to queue or subqueue based on my module. It can simply be done by implementing drupal_alter at end of nodequeue_api_*queue_access functions.

I am attaching a patch to this, it's a small change.

Possible use case: We have a site based on organic groups. Every organic group is in fact a magazine with several readers, contributors and editors. Using OG subqueues, every magazine has own queue to use for frontpage. Only group admins have access to change that queue though. I need to allow magazine editors to edit it too.

Simple code:

 /**
  * Implementation of hook_nodequeue_api_subqueue_access_alter().
  * 
  * Access to group subqueue: Magazine editor, Site admin, Group admin.
  */
function MYMODULE_nodequeue_api_subqueue_access_alter($access, $subqueue, $queue, $account) {
  // Special roles we use. $subqueue->reference is organic group ID.
  $roles = (array) $account->og_groups[$subqueue->reference]['csr_roles'];

  // Magazine editor, Site admin or Group admin.
  if ($roles[CSR_MAGAZINE_EDITOR_ROLE] || in_array('site admin', $account->roles) || $account->og_groups[$gid]['is_admin']) {
    $access = TRUE;
  } else {
    $access = FALSE;
  }
}