Reset buffer timestamp on ReleaseGraphicsResources

Reset the buffer timestamp when the buffers are released so if this glyph
is reinitialized and reused, the buffers will be rebuilt in their new state.
Otherwise they will attempt to use released buffers if their input data
timestamps haven't changed.

Rendering/OpenGL2/vtkOpenGLGlyph3DHelper.cxx

@@ -72,6 +72,7 @@ vtkOpenGLGlyph3DHelper::vtkOpenGLGlyph3DHelper()
 // Release any graphics resources that are being consumed by this mapper.
 void vtkOpenGLGlyph3DHelper::ReleaseGraphicsResources(vtkWindow* window)
 {
+  this->InstanceBuffersBuildTime = vtkTimeStamp();
   this->NormalMatrixBuffer->ReleaseGraphicsResources();
   this->MatrixBuffer->ReleaseGraphicsResources();
   this->ColorBuffer->ReleaseGraphicsResources();