Fix collerek/ormar#588 Bug in queryset count() method

tests/test_queries/test_aggr_functions.py

@@ -175,3 +175,15 @@ async def test_queryset_method():
         assert await author.books.max(["year", "title"]) == dict(
             year=1930, title="Book 3"
         )
+
+@pytest.mark.asyncio
+async def test_count_method():
+    async with database:
+        await sample_data()
+
+        count =  await Author.objects.select_related("books").count()
+        assert count == 1
+
+        # The legacy functionality
+        count =  await Author.objects.select_related("books").count(distinct=False)
+        assert count == 3