ogactivity does not track join events for groups requiring admin approval

Here's a modified version of ogactivity_og that properly handles the 'user approve' operation:

function ogactivity_og($op, $gid, $uid, $args) {
  switch ($op) {
    case 'user insert':
    case 'user delete':
    case 'user approve':

      // If the group join action requires approval then the is_active
      // arg will be 0 so in this case we bail out.
      if (array_key_exists('is_active', $args) && $args['is_active'] == 0) {
        return FALSE;
      }

      $node = node_load($gid);
      $type = 'ogaction';
      
      switch ($op) {
        case 'user insert':
        case 'user approve':
          $op = 'join';
          break;
        case 'user delete':
          $op = 'leave';
          break;
      }

      // Check if both type and operation are
      // enabled for activity. If not then stop here
      if (!in_array($type, variable_get('ogactivity_token_types', array($type)), TRUE) || 
        !in_array($op, variable_get('ogactivity_op_types', array($op)), TRUE)) {
        return FALSE;
      }

      // Privacy setting check
      $user = user_load(array('uid' => $uid));
      if (activity_user_privacy_optout($user)) {
        return FALSE;
      }

      // User hide activity permission check
      if (user_access('hide activity', $user)) {
        return FALSE;
      }

      $data = array(
        'operation'   => $op,
        'node-id'     => $node->nid,
        'node-title'  => $node->title,
        'node-type'   => $node->type,
      );

      $target_users_roles = array(
        ACTIVITY_ALL => 'all',
        $user->uid => 'author',
      );

      activity_insert($user->uid, 'ogactivity', $type, $op, $data, $target_users_roles);
      break;
  }
}