fsck is not a suitable command to check and repair an XFS filesystem ,use xfs_repair instead

In method `formatAndMount` in file utils/mount/mount_linux.go, command `fsck -a` is used to check and repair all kind of filesystems, including xfs.
But in fact `fsck` does nothing for xfs, we should use `xfs_repair` instead.

See the references:
https://linux.die.net/man/8/xfs_repair
https://linux.die.net/man/8/fsck.xfs