NFSv4: Allow security autonegotiation for submounts

In cases where the parent super block was not mounted with a 'sec=' line,
allow autonegotiation of security for the submounts.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index cc80085..a860ab5 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -1078,7 +1078,8 @@
 	if (error < 0)
 		goto error;
 
-	error = nfs4_server_common_setup(server, mntfh, false);
+	error = nfs4_server_common_setup(server, mntfh,
+			!(parent_server->flags & NFS_MOUNT_SECFLAVOUR));
 	if (error < 0)
 		goto error;