qapi/gen: Make _is_user_module() return bool

_is_user_module() returns thruth values.  The next commit wants it to
return bool.  Make it so.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201009161558.107041-27-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message rewritten]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi/gen.py

@@ -241,7 +241,7 @@ def __init__(self, prefix, what, user_blurb, builtin_blurb, pydoc):
 
     @staticmethod
     def _is_user_module(name):
-        return name and not name.startswith('./')
+        return bool(name and not name.startswith('./'))
 
     @staticmethod
     def _is_builtin_module(name):