Remove trailing zero parameter block sizes

This patch removes the use of trailing zeros in cost functions used in
unit tests as this will be an error once the sized cost function is
implemented using variadic templates.

Change-Id: I3e8a31b310ba7299fc6b1f012f540a3118cc7661

internal/ceres/parameter_block_ordering_test.cc

@@ -51,8 +51,8 @@ using std::vector;
 typedef Graph<ParameterBlock*> HessianGraph;
 typedef std::unordered_set<ParameterBlock*> VertexSet;
 
-template <int M, int N1 = 0, int N2 = 0, int N3 = 0>
-class DummyCostFunction: public SizedCostFunction<M, N1, N2, N3> {
+template <int M, int... Ns>
+class DummyCostFunction : public SizedCostFunction<M, Ns...> {
   virtual bool Evaluate(double const* const* parameters,
                         double* residuals,
                         double** jacobians) const {