Set a flag to indicate CCK is calling node_form

Within function content_admin_field_overview_form(), content.module invokes node_form(). Some modules may disable node_form, so does userreview (http://drupal.org/project/userreview), whioch I maintain. This leads to a situation where a field can be added but fields cannot be managed (see http://drupal.org/node/145679).

I suggest to add a special field to indicate that node_form has been invoked by content.module by adding a property _invoked_by_cck like this:

 // Create a dummy node and form and call hook_form_alter()
  // to produce an array of fields and weights added to the node by all modules.
  $dummy_node = new stdClass();
  $dummy_node->type = $type['type'];
  $dummy_node->_invoked_by_cck = true; // NEW! This indicates a CCK invoke
  $dummy_form_id = $type['type'] .'_node_form';
  $dummy_form = node_form($dummy_node);

What do you think?