PI nodes in external subset were not freed :-\ fixes bug #112842 Daniel

* tree.c: PI nodes in external subset were not freed :-\
  fixes bug #112842
Daniel
diff --git a/tree.c b/tree.c
index 8da828a..ff53a3e 100644
--- a/tree.c
+++ b/tree.c
@@ -904,7 +904,7 @@
 	 */
         while (c != NULL) {
 	    next = c->next;
-	    if (c->type == XML_COMMENT_NODE) {
+	    if ((c->type == XML_COMMENT_NODE) || (c->type == XML_PI_NODE)) {
 		xmlUnlinkNode(c);
 		xmlFreeNode(c);
 	    }