xfs_scrub: try to use XFS_SCRUB_IFLAG_FORCE_REBUILD

xfs_scrub: try to use XFS_SCRUB_IFLAG_FORCE_REBUILD

Now that we have a FORCE_REBUILD flag to the scrub ioctl, try to use
that over the (much noisier) error injection knob, which may or may not
even be enabled in the kernel config.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>