Add in vector include for ivar
Add in vector include for ivar

Some systems apparently were getting vector from somewhere else
and some systems do now. This way everyone gets it for the ivar.

keithroe/vtkoptix,SimVascular/VTK,sankhesh/VTK,SimVascular/VTK,SimVascular/VTK,sumedhasingla/VTK,sumedhasingla/VTK,sumedhasingla/VTK,sumedhasingla/VTK,sankhesh/VTK,keithroe/vtkoptix,sankhesh/VTK,sankhesh/VTK,keithroe/vtkoptix,sankhesh/VTK,keithroe/vtkoptix,sumedhasingla/VTK,SimVascular/VTK,sumedhasingla/VTK,keithroe/vtkoptix,keithroe/vtkoptix,SimVascular/VTK,sankhesh/VTK,sankhesh/VTK,sumedhasingla/VTK,SimVascular/VTK,sumedhasingla/VTK,SimVascular/VTK,sankhesh/VTK,keithroe/vtkoptix,SimVascular/VTK,keithroe/vtkoptix