Fixing cppcheck warning.
The warning is: Filters/FlowPaths/vtkCachingInterpolatedVelocityField.cxx:96: warning: Member variable 'IVFDataSetInfo::PCoords' is not assigned a value in 'IVFDataSetInfo::operator='.
The warning is: Filters/FlowPaths/vtkCachingInterpolatedVelocityField.cxx:96: warning: Member variable 'IVFDataSetInfo::PCoords' is not assigned a value in 'IVFDataSetInfo::operator='.