xfs: add debian initramfs hook to package

xfs: add debian initramfs hook to package

In Debian bug 904086, the reporter complained that xfs_repair wasn't
present in the initramfs, which prevented him from using shutdown -F to
force a filesystem fsck after a reboot.  Add a hook to put the xfs
utilities in the initramfs if xfs is the root filesystem.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>