Having no required fields for Multigroup throws error

This issue might be either similar to or caused by the discussion in http://drupal.org/node/577590, but if a multigroup is not required, and none of the fields in the group are required, it throws watchdog errors when creating or editing a content type that has multigroup fields in it. I traced the problem to the two functions that deal with the requirement issues listed in the node in the link above.

content_multigroup_node_form_pre_render(&$form) and _content_multigroup_node_form_after_build($form, &$form_state)

In both these function it loops through the forms elements that are multigroups, then it grabs the array keys for the field names, and the array isn't empty it performs the fix for validation. However since the conditional checks if $required_fields is populated after the line $required_fields = array_keys($form['#multigroup_required_fields'][$group_name]); it throws a watchdog error because it passes NULL to array_keys() if there are no required fields. I feel the conditional should check if $form['#multigroup_required_fields'][$group_name] is populated and then get the array keys.

The error doesn't cause any functional issues since nothing has to happen if the fields aren't required, but it fills up the logs pretty quickly when creating a lot of nodes with multigroups. I have created a patch which makes this change. When I make the change the error goes away. I also tested it with required fields to make sure the functions work as expected and it seems to work without any issues.