Fixed crash on missing data key in field

This may occur if datatables supplies a null or empty string, which is parsed as an unsearchable/-sortable field. (See filters.py/get_fields)

Author: Invisi

rest_framework_datatables/django_filters/backends.py

@@ -62,6 +62,9 @@ def parse_datatables_query(self, request, view):
         form_fields = {}
         field_queries = {}
         for f in query['fields']:
+            if 'data' not in f:
+                continue
+
             form_fields[f['data']] = f['search_value']
             field_queries[f['data']] = f
         query['form_fields'] = form_fields