Remove disabled legacy code in ffplay.

The code was setting aspect ratio from the DTG active format, and was
present and disabled since the creation of ffplay.

See thread:
Subject: [FFmpeg-devel] [PATCH] Cosmetics: adopt compact notation in
        disabled code.
Date: Sat, 12 Feb 2011 18:46:19 +0100

Signed-off-by: Mans Rullgard <mans@mansr.com>