Added Set that takes no arguments.

The goal is to allow Python wrappers to add IntegerVectors that are empty
to the information objects.

Common/vtkInformationIntegerVectorKey.cxx

@@ -64,6 +64,13 @@ void vtkInformationIntegerVectorKey::Append(vtkInformation* info, int value)
     }
 }
 
+//----------------------------------------------------------------------------
+void vtkInformationIntegerVectorKey::Set(vtkInformation* info)
+{
+  int someVal;
+  this->Set(info, &someVal, 0);
+}
+
 //----------------------------------------------------------------------------
 void vtkInformationIntegerVectorKey::Set(vtkInformation* info, int* value,
                                          int length)

Common/vtkInformationIntegerVectorKey.h

@@ -39,6 +39,7 @@ public:
   // information object.
   void Append(vtkInformation* info, int value);
   void Set(vtkInformation* info, int* value, int length);
+  void Set(vtkInformation* info);
   int* Get(vtkInformation* info);
   int  Get(vtkInformation* info, int idx);
   void Get(vtkInformation* info, int* value);