xfs/490: fix failure due to deprecated ikeep mount option

xfs/490: fix failure due to deprecated ikeep mount option

The ikeep mount option has been deprecated as of kernel commit
b9a176e54162 ("xfs: remove deprecated mount options"), and after commit
3e7ec343f066 ("xfs: loudly complain about defunct mount options") there
is a warning emitted when testing v5 filesystems.

Fix it by explicitly requiring and formatting scratch to nocrc/v4, as
the test cannot otherwise be triggered on v5 without the ikeep option.

Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>