Removed unnecessary shallow copy.
Removed unnecessary shallow copy.

Shallow copying the input to the internal multi-block dataset
was causing locators and cell links to be recomputed when the
seeds changed but the input did not.

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