ffmpeg 0.11 removed av_open_input_file, and current git libav removed
av_find_stream_info and avcodec_open. #if uses of these functions to
build on new ffmpeg/libav without removing ffmpeg 0.6 compatibility.
There's still lots of deprecation warnings, but it builds.

Thanks to Christoph Feck for pointing out the release of ffmpeg 0.11 broke
av_open_input_file and the toAscii() -> toLocal8Bit() fix.

REVIEW:105073