qapi/source.py: delint with pylint

Shush an error and leave a hint for future cleanups when we're allowed
to use Python 3.7+.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Tested-by: Cleber Rosa <crosa@redhat.com>
Message-Id: <20201009161558.107041-26-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi/pylintrc

@@ -7,7 +7,6 @@ ignore-patterns=error.py,
                 gen.py,
                 parser.py,
                 schema.py,
-                source.py,
                 types.py,
                 visit.py,
 

scripts/qapi/source.py

@@ -15,6 +15,9 @@ from typing import List, Optional, TypeVar
 
 
 class QAPISchemaPragma:
+    # Replace with @dataclass in Python 3.7+
+    # pylint: disable=too-few-public-methods
+
     def __init__(self) -> None:
         # Are documentation comments required?
         self.doc_required = False