nfsd4: return default lease period

I don't have a good rationale for the lease period, but 90 seconds seems
long, and as long as we're allowing the server to extend the grace
period up to double the lease period, let's half the default to 45.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfsctl.c

@@ -1237,8 +1237,8 @@ static __net_init int nfsd_init_net(struct net *net)
 	retval = nfsd_idmap_init(net);
 	if (retval)
 		goto out_idmap_error;
-	nn->nfsd4_lease = 90;	/* default lease time */
-	nn->nfsd4_grace = 90;
+	nn->nfsd4_lease = 45;	/* default lease time */
+	nn->nfsd4_grace = 45;
 	nn->somebody_reclaimed = false;
 	nn->clverifier_counter = prandom_u32();
 	nn->clientid_counter = prandom_u32();