If size == 1 and buf[0] == 0 and buf[1] == 0 (the first byte after the
buffer), it would set size = -1 and crash in the later memcpy.


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@22469 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b