ext4: avoid trying to kfree an ERR_PTR pointer

Thanks to Dan Carpenter for extending smatch to find bugs like this.
(This was found using a development version of smatch.)

Fixes: 36de928641ee48b2078d3fe9514242aaa2f92013
Reported-by: Dan Carpenter <dan.carpenter@oracle.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 90a3cdc..603e4eb 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3240,6 +3240,7 @@
 				 &new.de, &new.inlined);
 	if (IS_ERR(new.bh)) {
 		retval = PTR_ERR(new.bh);
+		new.bh = NULL;
 		goto end_rename;
 	}
 	if (new.bh) {
@@ -3386,6 +3387,7 @@
 				 &new.de, &new.inlined);
 	if (IS_ERR(new.bh)) {
 		retval = PTR_ERR(new.bh);
+		new.bh = NULL;
 		goto end_rename;
 	}