xfs_repair: fix getsubopt name definitions to use enums

xfs_repair: fix getsubopt name definitions to use enums

Convert the getsubopt usage in xfs_repair to use enums and explicitly
initialized array elements, similar to mkfs.  This also fixes the hole
in the o_opts table caused by 42fa89bc1b8dc8 ("xfs_repair: remove
pre_65_beta option") that causes segfaults in xfs/179 and xfs/202.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Fixes: 42fa89bc1b ("xfs_repair: remove pre_65_beta option")
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>