ext4: don't pass freed handle to ext4_walk_page_buffers

This is harmless, since ext4_walk_page_buffers only passes the handle
onto the callback function, and in this call site the function in
question, bput_one(), doesn't actually use the handle.  But there's no
point passing in an invalid handle, and it creates a Coverity warning,
so let's just clean it up.

Addresses-Coverity-Id: #1091168
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/inode.c

@@ -1772,7 +1772,7 @@ static int __ext4_journalled_writepage(struct page *page,
 		ret = err;
 
 	if (!ext4_has_inline_data(inode))
-		ext4_walk_page_buffers(handle, page_bufs, 0, len,
+		ext4_walk_page_buffers(NULL, page_bufs, 0, len,
 				       NULL, bput_one);
 	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
 out: