Fix header in vtkMPIUtilities

Change-Id: I1b665cdaf91d974adf28d275776661029ed82a60
Various test improvements

Change-Id: I2429f801e62124626ba382ae28888a0f7adb2971
Code improvements

Change-Id: If1b932f9935417b3129ec2882a00ae46bcc9c5f6