Unbreak the `importl10n` command by updating the links to point to hg.mozilla.org instead of mxr

Currently `importl10n` fails, since mxr.mozilla.org has been down for a while. Based on discussions in #developers, it isn't clear to me if/when it'll be available again.
Furthermore, I'm not sure why we're even getting the l10n files through a code search tool, rather than just using the official Mozilla repository directly.

external/importL10n/locales.js

@@ -17,7 +17,7 @@
 'use strict';
 
 var fs = require('fs');
-var http = require('http');
+var https = require('https');
 var path = require('path');
 
 // Defines all languages that have a translation at mozilla-aurora.
@@ -47,9 +47,8 @@ function downloadLanguageFiles(root, langCode, callback) {
   // Constants for constructing the URLs. Translations are taken from the
   // Aurora channel as those are the most recent ones. The Nightly channel
   // does not provide all translations.
-  var MOZCENTRAL_ROOT = 'http://mxr.mozilla.org/l10n-mozilla-aurora/source/';
+  var MOZ_AURORA_ROOT = 'https://hg.mozilla.org/releases/l10n/mozilla-aurora/';
-  var MOZCENTRAL_PDFJS_DIR = '/browser/pdfviewer/';
+  var MOZ_AURORA_PDFJS_DIR = '/raw-file/tip/browser/pdfviewer/';
-  var MOZCENTRAL_RAW_FLAG = '?raw=1';
 
   // Defines which files to download for each language.
   var files = ['chrome.properties', 'viewer.properties'];
@@ -63,9 +62,8 @@ function downloadLanguageFiles(root, langCode, callback) {
   // Download the necessary files for this language.
   files.forEach(function(fileName) {
     var outputPath = path.join(outputDir, fileName);
-    var url = MOZCENTRAL_ROOT + langCode + MOZCENTRAL_PDFJS_DIR +
+    var url = MOZ_AURORA_ROOT + langCode + MOZ_AURORA_PDFJS_DIR + fileName;
-              fileName + MOZCENTRAL_RAW_FLAG;
+    var request = https.get(url, function(response) {
-    var request = http.get(url, function(response) {
       var content = '';
       response.setEncoding('utf8');
       response.on("data", function(chunk) {