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/resize.c b/fs/ext4/resize.c
index bb0e80f..1e43b90 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -575,6 +575,7 @@
 		bh = bclean(handle, sb, block);
 		if (IS_ERR(bh)) {
 			err = PTR_ERR(bh);
+			bh = NULL;
 			goto out;
 		}
 		overhead = ext4_group_overhead_blocks(sb, group);
@@ -603,6 +604,7 @@
 		bh = bclean(handle, sb, block);
 		if (IS_ERR(bh)) {
 			err = PTR_ERR(bh);
+			bh = NULL;
 			goto out;
 		}