Sigh... After the recent changes, another regression appeared. This
time, the VO window wasn't cleared when changing from video to a non-
video file (such as audio-only with no cover art). Fix this by properly
taking the handle_force_window() bool parameter into account.
Also, the info message could be printed twice, which is harmless but
ugly. So just remove the message.
Also, do some more minor cleanups (like fixing the comment, which was
completely outdated).