putname(): IS_ERR_OR_NULL() is wrong here

Mixing NULL and ERR_PTR() just in case is a Bad Idea(tm).  For
struct filename the former is wrong - failures are reported
as ERR_PTR(...), not as NULL.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Author: Al Viro

fs/namei.c

@@ -255,7 +255,7 @@ getname_kernel(const char * filename)
 
 void putname(struct filename *name)
 {
-	if (IS_ERR_OR_NULL(name))
+	if (IS_ERR(name))
 		return;
 
 	BUG_ON(name->refcnt <= 0);