message: ffmpeg: update 3.3.4
diff: -# Binary branch name: ffmpeg/master_20170704
  -# Binaries were created for OpenCV: f670a9927026629a4083e05a1612f0adcad7727e
  -set(FFMPEG_BINARIES_COMMIT "a86e53eb35737a50e5100e26af3aa1d29e810890")
  -set(FFMPEG_FILE_HASH_BIN32 "79c35cc654778e66237444bc562afbca")
  -set(FFMPEG_FILE_HASH_BIN64 "0dc72775ec3c14d1e049f51dc1280dbb")
  +# Binary branch name: ffmpeg/master_20171009
  +# Binaries were created for OpenCV: 8ac2c5d620b467d3f22802e96c88ddde6da707af
  +set(FFMPEG_BINARIES_COMMIT "66b1fed06cf3510235f367f96aa26da5cb234a15")
  +set(FFMPEG_FILE_HASH_BIN32 "3ae76b105113d944984b2351c61e21c6")
  +set(FFMPEG_FILE_HASH_BIN64 "cf3bb5bc9d393b022ea7a42eb63e794d")
  set(FFMPEG_FILE_HASH_CMAKE "ec59008da403fb18ab3c1ed66aed583b")
  function(download_win_ffmpeg script_var)
  