Adding in warning if the input vtkPointData structures is different.

These filters use vtkDataSetAttributes to interpolate input
point data to the output polydata so we need to make sure
that the point data structures match on all processes and
data sets. If they don't, the filters now return an error
and fail.

Change-Id: I639964871d8cf9fdd398e821560050bedd937143
Merge topic 'flowpath_filters_check_arrays' into master

eab902ac Adding in warning if the input vtkPointData structures is different.