[1.5.x] Fixed #16408 -- Re-fixed value conversion with Spatialite backend

Backport of 0907d3c6f from master.

django/contrib/gis/db/models/sql/query.py

@@ -72,6 +72,8 @@ class GeoQuery(sql.Query):
             value = Area(**{field.area_att : value})
         elif isinstance(field, (GeomField, GeometryField)) and value:
             value = Geometry(value)
+        elif field is not None:
+            return super(GeoQuery, self).convert_values(value, field, connection)
         return value
 
     def get_aggregation(self, using):

django/contrib/gis/tests/geoapp/test_regress.py

@@ -5,7 +5,7 @@ from datetime import datetime
 
 from django.contrib.gis.tests.utils import no_mysql, no_spatialite
 from django.contrib.gis.shortcuts import render_to_kmz
-from django.db.models import Count
+from django.db.models import Count, Min
 from django.test import TestCase
 
 from .models import City, PennsylvaniaCity, State, Truth
@@ -50,6 +50,7 @@ class GeoRegressionTests(TestCase):
         mansfield = PennsylvaniaCity.objects.create(name='Mansfield', county='Tioga', point='POINT(-77.071445 41.823881)',
                                                     founded=founded)
         self.assertEqual(founded, PennsylvaniaCity.objects.dates('founded', 'day')[0])
+        self.assertEqual(founded, PennsylvaniaCity.objects.aggregate(Min('founded'))['founded__min'])
 
     def test_empty_count(self):
          "Testing that PostGISAdapter.__eq__ does check empty strings. See #13670."