A handle of flake8 fixes

django/contrib/gis/db/backends/postgis/schema.py

-from django.conf import settings
 from django.db.backends.postgresql_psycopg2.schema import DatabaseSchemaEditor
-from django.utils.functional import cached_property
 
 
 class PostGISSchemaEditor(DatabaseSchemaEditor):

django/contrib/gis/db/models/fields.py

@@ -112,9 +112,9 @@ class GeometryField(Field):
         kwargs['srid'] = self.srid
         if self.dim != 2:
             kwargs['dim'] = self.dim
-        if self.spatial_index != True:
+        if self.spatial_index is not True:
             kwargs['spatial_index'] = self.spatial_index
-        if self.geography != False:
+        if self.geography is not False:
             kwargs['geography'] = self.geography
         return name, path, args, kwargs