xfs: fix uninitialized variable in xfs_attr3_leaf_inactive

commit 54027a49 upstream.

Dan Carpenter pointed out that error is uninitialized.  While there
never should be an attr leaf block with zero entries, let's not leave
that logic bomb there.

Fixes: 0bb9d159 ("xfs: streamline xfs_attr3_leaf_inactive")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>