functionObjects: Simplified the handling of the post-processing mode

Replaced the 'postProcess' argument to the 'write' and 'execute'
functions with the single static member 'postProcess' in the
functionObject base-class.

src/functionObjects/field/components/components.C

@@ -76,7 +76,7 @@ Foam::functionObjects::components::~components()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-bool Foam::functionObjects::components::write(const bool postProcess)
+bool Foam::functionObjects::components::write()
 {
     bool written = true;