NFSv4.1: need to put_layout_hdr on _pnfs_return_layout error path

We always get a reference on the layout header and we rely on
nfs4_layoutreturn_release to put it.  If we hit an allocation error
before starting the rpc proc we bail out early without dereferncing
the layout header properly.

Signed-off-by: Benny Halevy <benny@tonian.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index d066aad..8f95822 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -652,6 +652,7 @@
 	lrp = kzalloc(sizeof(*lrp), GFP_KERNEL);
 	if (unlikely(lrp == NULL)) {
 		status = -ENOMEM;
+		put_layout_hdr(lo);
 		goto out;
 	}