Patch the experimental NFS server is a manner analagous to
r197525, so that the creation verifier is handled correctly
in va_atime for 64bit architectures. There were two problems.
One was that the code incorrectly assumed that
sizeof (struct timespec) == 8 and the other was that the tv_sec
field needs to be assigned from a signed 32bit integer, so that
sign extension occurs on 64bit architectures. This is required
for correct operation when exporting ZFS volumes.
Tested by: gerrit at pmp.uni-hannover.de
Reviewed by: pjd
52b239b029