If we are using the same version/fsid as a current filehandle, then there is
no need to verify the the numbers are valid for this export, and they must be
(we used them to find this export).

This allows us to simplify the fsid selection code.

Also change "ref_fh_version" and "ref_fh_fsid_type" to "version" and
"fsid_type", as the important thing isn't that they are the version/type of
the reference filehandle, but they are the chosen type for the new filehandle.

And tidy up some indenting.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>