Add new "lustre" fs type which supports only zeroconf mounts.

Add new "lustre" fs type which supports only zeroconf mounts.
 - old zeroconf client code removed from lustre-lite, and the lconf
   --zeroconf option deleted
 - common code factored out for ll/lustre fill_super and put_super
 - lconf still uses lustre_lite (but not for long)

llmount will be used by mount for lustre filesystems if copied to
/sbin/mount.lustre:

  mount -t lustre mds_host:/mds_servicee/profile  /mnt/lustre

Multiple mounts of the same filesystem are supported.

Remove unused mds and filter nspath code.