Fix macro bug in docbook exporter

lisp/org-docbook.el

@@ -419,9 +419,10 @@ publishing directory."
 			     (+ (funcall outline-level)
 				(if org-odd-levels-only 1 0)))
 			 0))
-	 (opt-plist (if subtree-p
-			(org-export-add-subtree-options opt-plist rbeg)
-		      opt-plist))
+	 (opt-plist (setq org-export-opt-plist
+			  (if subtree-p
+			      (org-export-add-subtree-options opt-plist rbeg)
+			    opt-plist)))
 	 ;; The following two are dynamically scoped into other
 	 ;; routines below.
 	 (org-current-export-dir