nfsd4: make delegation stateid's seqid start at 1

Thanks to Casey for reminding me that 5661 gives a special meaning to a
value of 0 in the stateid's seqid field, so all stateid's should start
out with si_generation 1.  We were doing that in the open and lock
cases for minorversion 1, but not for the delegation stateid, and not
for openstateid's with v4.0.

It doesn't *really* matter much for v4.0 or for delegation stateid's
(which never get the seqid field incremented), but we may as well do the
same for all of them.

Reported-by: Casey Bodley <cbodley@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>