Revert "functionObject: change default behavior of 'end()' to do nothing...

Revert "functionObject: change default behavior of 'end()' to do nothing rather than calling execute and write"

This reverts commit 4fda55b2.

src/OpenFOAM/db/functionObjects/functionObject/functionObject.C

@@ -136,7 +136,7 @@ bool Foam::functionObject::read(const dictionary& dict)
 
 bool Foam::functionObject::end()
 {
-    return true;
+    return execute() && write();
 }