Remove old file from concat step

async-queue is no longer needed in this project, so remove it from the concat step of the dist build.

@@ -24,7 +24,6 @@ module.exports = function(grunt) {
       dist: {
         nonull: true,
         src: ['src/videojs-hls.js',
-              'src/async-queue.js',
               'src/flv-tag.js',
               'src/exp-golomb.js',
               'src/h264-stream.js',