modules::shockFluid: Clear temporary fluxed if NCC interfaces are updated

Resolves bug-report https://bugs.openfoam.org/view.php?id=4020

applications/modules/shockFluid/shockFluid.C

@@ -24,6 +24,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "shockFluid.H"
+#include "fvMeshStitcher.H"
 #include "localEulerDdtScheme.H"
 #include "hydrostaticInitialisation.H"
 #include "fvcMeshPhi.H"
@@ -255,7 +256,7 @@ void Foam::solvers::shockFluid::preSolve()
 
     fvModels().preUpdateMesh();
 
-    if (mesh.topoChanging())
+    if (mesh.topoChanging() || mesh.stitcher().stitches())
     {
         pos.clear();
         neg.clear();