Keep track of gl_block state (added in bba19b88 console: block rendering
until client is done) in QemuConsole and allow to query it.  This way
we can avoid state inconsistencies in case different code paths make use
of this.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 1474617028-3979-2-git-send-email-kraxel@redhat.com