BUG: sampledPlane: fix parallel running on subset. Fixes #463.

src/sampling/sampledSurface/sampledPlane/sampledPlane.C

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -139,7 +139,7 @@ bool Foam::sampledPlane::update()
 
     labelList selectedCells = mesh().cellZones().findMatching(zoneKey_).used();
 
-    if (selectedCells.empty())
+    if (returnReduce(selectedCells.empty(), andOp<bool>()))
     {
         reCut(mesh(), triangulate_);
     }