Remove unnecessary select for removing an auth code grant (#1568)

Author: q0w

AUTHORS

@@ -123,3 +123,4 @@ Yaroslav Halchenko
 Yuri Savin
 Miriam Forner
 Alex Kerkum
+q0w

oauth2_provider/oauth2_validators.py

@@ -322,10 +322,8 @@ def invalidate_authorization_code(self, client_id, code, request, *args, **kwarg
 
         :raises: InvalidGrantError if the grant does not exist.
         """
-        try:
-            grant = Grant.objects.get(code=code, application=request.client)
-            grant.delete()
-        except Grant.DoesNotExist:
+        deleted_grant_count, _ = Grant.objects.filter(code=code, application=request.client).delete()
+        if not deleted_grant_count:
             raise errors.InvalidGrantError(request=request)
 
     def validate_client_id(self, client_id, request, *args, **kwargs):