Removed unnecessary files.

tutorials/incompressible/MRFSimpleFoam/mixerVessel2D/system/cellSetDict

-/*--------------------------------*- C++ -*----------------------------------*\
-| =========                 |                                                 |
-| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
-|  \\    /   O peration     | Version:  1.6                                   |
-|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
-|    \\/     M anipulation  |                                                 |
-\*---------------------------------------------------------------------------*/
-FoamFile
-{
-    version     2.0;
-    format      ascii;
-    class       dictionary;
-    location    "system";
-    object      cellSetDict;
-}
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-name            rotor;
-
-action          new;
-
-topoSetSources  ( zoneToCell { name rotor ; } );
-
-
-// ************************************************************************* //