PBiCGStab: Instantiate for symmetric and asymmetric matrices

PBiCGStab has proved more reliable than PCG for solving the pressure equation in
compressible systems.

src/OpenFOAM/matrices/lduMatrix/solvers/PBiCGStab/PBiCGStab.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2016 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2016-2017 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -31,6 +31,9 @@ namespace Foam
 {
     defineTypeNameAndDebug(PBiCGStab, 0);
 
+    lduMatrix::solver::addsymMatrixConstructorToTable<PBiCGStab>
+        addPBiCGStabSymMatrixConstructorToTable_;
+
     lduMatrix::solver::addasymMatrixConstructorToTable<PBiCGStab>
         addPBiCGStabAsymMatrixConstructorToTable_;
 }