Unable to delete wiki pages (directories) via webdav interface.

One some webdav clients (Mac Finder), it's not possible to delete wiki pages. This occurs because wiki.txt and wiki.xml can't be deleted individually (they reappear when refreshed). Some clients follow a recursive delete procedure and after deleting wiki.txt and wiki.xml they make a check to see if they were actually deleted. When this check fails, the whole delete fails.