[NL/DOF] Constify node_adjacency_table.

Remove no longer required default constructor.

MeshLib/NodeAdjacencyTable.h

@@ -32,10 +32,7 @@ namespace MeshLib
 class
 NodeAdjacencyTable
 {
-
 public:
-    NodeAdjacencyTable() = default;
-
     explicit
     NodeAdjacencyTable(std::vector<Node*> const& nodes)
     {

NumLib/DOF/ComputeSparsityPattern.cpp

@@ -36,8 +36,7 @@ GlobalSparsityPattern computeSparsityPatternPETSc(
 GlobalSparsityPattern computeSparsityPatternNonPETSc(
     NumLib::LocalToGlobalIndexMap const& dof_table, MeshLib::Mesh const& mesh)
 {
-    MeshLib::NodeAdjacencyTable node_adjacency_table;
-    node_adjacency_table.createTable(mesh.getNodes());
+    MeshLib::NodeAdjacencyTable const node_adjacency_table(mesh.getNodes());
 
     // A mapping   mesh node id -> global indices
     // It acts as a cache for dof table queries.