nfsd4: move rq_flavor into svc_cred

Move the rq_flavor into struct svc_cred, and use it in setclientid and
exchange_id comparisons as well.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index ec16364..ba23349 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -904,13 +904,13 @@
 		return 0;
 	/* ip-address based client; check sec= export option: */
 	for (f = exp->ex_flavors; f < end; f++) {
-		if (f->pseudoflavor == rqstp->rq_flavor)
+		if (f->pseudoflavor == rqstp->rq_cred.cr_flavor)
 			return 0;
 	}
 	/* defaults in absence of sec= options: */
 	if (exp->ex_nflavors == 0) {
-		if (rqstp->rq_flavor == RPC_AUTH_NULL ||
-		    rqstp->rq_flavor == RPC_AUTH_UNIX)
+		if (rqstp->rq_cred.cr_flavor == RPC_AUTH_NULL ||
+		    rqstp->rq_cred.cr_flavor == RPC_AUTH_UNIX)
 			return 0;
 	}
 	return nfserr_wrongsec;