affs: testing the wrong variable

The intent was to verify that bh = affs_bread_ino(...) returned a valid
pointer.  We checked "ext_bh" earlier in the function and it's valid
here.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/affs/file.c

@@ -894,9 +894,9 @@ affs_truncate(struct inode *inode)
 		if (AFFS_SB(sb)->s_flags & SF_OFS) {
 			struct buffer_head *bh = affs_bread_ino(inode, last_blk, 0);
 			u32 tmp;
-			if (IS_ERR(ext_bh)) {
+			if (IS_ERR(bh)) {
 				affs_warning(sb, "truncate", "unexpected read error for last block %u (%d)",
-					     ext, PTR_ERR(ext_bh));
+					     ext, PTR_ERR(bh));
 				return;
 			}
 			tmp = be32_to_cpu(AFFS_DATA_HEAD(bh)->next);