patch 8.0.1459: cannot handle change of directory

Problem:    Cannot handle change of directory.
Solution:   Add the DirChanged autocommand event. (Andy Massimino,
            closes #888)  Avoid changing directory for 'autochdir' too often.
diff --git a/src/netbeans.c b/src/netbeans.c
index c906d28..199cfd6 100644
--- a/src/netbeans.c
+++ b/src/netbeans.c
@@ -2663,7 +2663,7 @@
     nbdebug(("EVT: %s", buffer));
 
     nb_send(buffer, "netbeans_file_opened");
-    if (p_acd && vim_chdirfile(bufp->b_ffname) == OK)
+    if (p_acd && vim_chdirfile(bufp->b_ffname, "auto") == OK)
 	shorten_fnames(TRUE);
 }