NFSv4: Fix security auto-negotiation

NFSv4 security auto-negotiation has been broken since
commit 4580a92d44e2b21c2254fa5fef0f1bfb43c82318 (NFS:
Use server-recommended security flavor by default (NFSv3))
because nfs4_try_mount() will automatically select AUTH_SYS
if it sees no auth flavours.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
diff --git a/fs/nfs/nfs4getroot.c b/fs/nfs/nfs4getroot.c
index 549462e..c0b3a16 100644
--- a/fs/nfs/nfs4getroot.c
+++ b/fs/nfs/nfs4getroot.c
@@ -9,7 +9,7 @@
 
 #define NFSDBG_FACILITY		NFSDBG_CLIENT
 
-int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh)
+int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh, bool auth_probe)
 {
 	struct nfs_fsinfo fsinfo;
 	int ret = -ENOMEM;
@@ -21,7 +21,7 @@
 		goto out;
 
 	/* Start by getting the root filehandle from the server */
-	ret = nfs4_proc_get_rootfh(server, mntfh, &fsinfo);
+	ret = nfs4_proc_get_rootfh(server, mntfh, &fsinfo, auth_probe);
 	if (ret < 0) {
 		dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret);
 		goto out;