Further fixes

* fixes race condition on geometry conflict calculation if performed in background process
* simplifies access to smaller buffered geometry
* adds mapping of "qm"->"m2" for UnitChoice in API usage for backwards compatibility

konova/utils/wfs/spatial.py

@@ -91,7 +91,7 @@ class ParcelWFSFetcher(AbstractWFSFetcher):
         geom = Geometry.objects.filter(
             id=self.geometry_id
         ).annotate(
-            smaller=Func(F('geom'), -0.001, function="ST_Buffer")
+            smaller=Func(F('geom'), -0.001, function="ST_Buffer")  # same as geometry.geom_small_buffered but for QuerySet
         ).annotate(
             gml=AsGML(MakeValid('smaller'))
         ).first()