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/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 12e4897..88962cf 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -768,7 +768,7 @@
 	svc_putnl(resv, RPC_AUTH_NULL);
 	svc_putnl(resv, 0);
 
-	rqstp->rq_flavor = RPC_AUTH_NULL;
+	rqstp->rq_cred.cr_flavor = RPC_AUTH_NULL;
 	return SVC_OK;
 }
 
@@ -839,7 +839,7 @@
 	svc_putnl(resv, RPC_AUTH_NULL);
 	svc_putnl(resv, 0);
 
-	rqstp->rq_flavor = RPC_AUTH_UNIX;
+	rqstp->rq_cred.cr_flavor = RPC_AUTH_UNIX;
 	return SVC_OK;
 
 badcred: