qapi/error.py: enable mypy checks

Signed-off-by: John Snow <jsnow@redhat.com>

Message-Id: <20210421192233.3542904-9-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi/mypy.ini

@@ -3,11 +3,6 @@ strict = True
 disallow_untyped_calls = False
 python_version = 3.6
 
-[mypy-qapi.error]
-disallow_untyped_defs = False
-disallow_incomplete_defs = False
-check_untyped_defs = False
-
 [mypy-qapi.parser]
 disallow_untyped_defs = False
 disallow_incomplete_defs = False