VMD playing error patch by (Kostya (cannonball bw-team com>)

VMD playing error patch by (Kostya (cannonball bw-team com>)
"I recently got a game called Lighthouse from Sierra with FMV in VMD
format. Some of them played OK, some of them FFmpeg refused to open,
some caused a crash.

I investigated files which couldn't be opened by FFmpeg and it appeared
that they had no audio (and bytes 2-3 from beginning of file contained
01 00, all other have 00 00 insted). Attached patch fixes this issue."

Originally committed as revision 3934 to svn://svn.ffmpeg.org/ffmpeg/trunk