FIX: media/liveleak.lua: Sanitize input for LuaJSON

Otherwise the script will throw an error that looks like:
  /usr/share/lua/5.1/json/decode/util.lua:40: unexpected character @
  character: 733 17:16 [e] line:

Signed-off-by: Toni Gundogdu <legatvs@gmail.com>