Fix for bug 15830
Fix for bug 15830

Texture creation does not unbind the active texture anymore.

Reasoning:
Sometimes render methods created new textures, unbinding the textures set before the render call. It was mostly the case with the depth peeling pass, where 'opaqueZ' depth buffer was sometimes unbound preventing drawing the transparent objects.

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