NFSv4/pNFS: Return an error if _nfs4_pnfs_v3_ds_connect can't load NFSv3

Currently we fail to return an error if the NFSv3 module failed to load
when we're trying to connect to a pNFS data server.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/pnfs_nfs.c

@@ -855,7 +855,7 @@ static int _nfs4_pnfs_v3_ds_connect(struct nfs_server *mds_srv,
 	dprintk("--> %s DS %s\n", __func__, ds->ds_remotestr);
 
 	if (!load_v3_ds_connect())
-		goto out;
+		return -EPROTONOSUPPORT;
 
 	list_for_each_entry(da, &ds->ds_addrs, da_node) {
 		dprintk("%s: DS %s: trying address %s\n",