Correct field name

The field name was incorrect since commit 055c0755.

Inst_eddies/Analysis/filter.py

@@ -41,13 +41,13 @@ with shapefile.Reader(path.join(args.input_dir, "extremum")) as extremum, \
         in zip(extremum, outermost_cont, max_speed_cont):
         if accept.accept(shape_rec_extr, shape_rec_outer, shape_rec_max):
             if args.renumber:
-                if shape_rec_extr.record.date_index == last_date_written:
+                if shape_rec_extr.record.date == last_date_written:
                     eddy_index += 1
                 else:
                     ishape_last.append((last_date_written,
                                         len(extremum_filt) - 1))
                     eddy_index = 1
-                    last_date_written = shape_rec_extr.record.date_index
+                    last_date_written = shape_rec_extr.record.date
 
             for sr, w in zip([shape_rec_extr, shape_rec_outer, shape_rec_max],
                              [extremum_filt, outermost_cont_filt,