[XFS] rename error2 goto label in xfs_fs_fill_super

SGI-PV: 981951
SGI-Modid: xfs-linux-melb:xfs-kern:31198a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>