fix ffmpeg 2.8 ffprobe handling (when no [format] line in ffprobe output)
fix ffmpeg 2.8 ffprobe handling (when no [format] line in ffprobe output)

fluent-ffmpeg/node-fluent-ffmpeg,rhodgkins/node-fluent-ffmpeg,rhodgkins/node-fluent-ffmpeg,streamablevideo/node-fluent-ffmpeg,fluent-ffmpeg/node-fluent-ffmpeg,streamablevideo/node-fluent-ffmpeg,fluent-ffmpeg/node-fluent-ffmpeg,streamablevideo/node-fluent-ffmpeg