COMP: TensorI.H - provide default case to suppress compiler warning

src/OpenFOAM/primitives/Tensor/TensorI.H

@@ -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) 2016 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -314,6 +314,11 @@ inline Foam::Vector<Cmpt> Foam::Tensor<Cmpt>::vectorComponent
             return z();
             break;
     }
+
+    FatalErrorInFunction
+        << "Unhandled component " << cmpt << abort(FatalError);
+
+    return x();
 }