nfs: allow different protocol in nfs_initiate_commit

pnfs flexfile layout client may want to use NFSv3 ops rather
than the default MDS v4 ops.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index 23c851d..c87f664 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -278,6 +278,7 @@
 		if (!data->lseg) {
 			nfs_init_commit(data, mds_pages, NULL, cinfo);
 			nfs_initiate_commit(NFS_CLIENT(inode), data,
+					    NFS_PROTO(data->inode),
 					    data->mds_ops, how, 0);
 		} else {
 			struct pnfs_commit_bucket *buckets;