typeshed (included in mypy) recently updated to improve the typing for
WriteTransport objects. I was working around this, but now there's a
version where I shouldn't work around it.

Unfortunately this creates some minor ugliness if I want to support both
pre- and post-0.950 versions. For now, for my sanity, just disable the
unused-ignores warning.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220526000921.1581503-2-jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>