Remove unused Chromevox classic background script.

chrome/browser/resources/chromeos/chromevox/manifest.json.jinja2

 {
 {%if key is defined %}
   "key": "{{key}}",
 {% endif %}
   "manifest_version": 2,
   "name": "__MSG_CHROMEVOX_NAME__",
   "version": "{{set_version}}",
   "description": "__MSG_CHROMEVOX_DESCRIPTION__",
 {% if is_guest_manifest == '1' %}
   "incognito": "split",
@@ skipping 12 matching lines @@
     "storage",
     "tabs",
     "tts",
     "virtualKeyboardPrivate",
     "<all_urls>"
   ],
   "content_scripts": [
     {
       "matches": [ "<all_urls>" ],
       "exclude_globs": [
-          "chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromevox/background/background.html"
+          "chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/cvox2/background/background.html"
       ],
       "all_frames": true,
       "js": [
 {% if is_js_compressed == '1' %}
         "chromeVoxChromePageScript.js"
 {% else %}
         "closure/closure_preinit.js",
         "closure/base.js",
         "deps.js",
         "chromevox/injected/loader.js"
@@ skipping 244 matching lines @@
       "description": "__MSG_CHROMEVOX_SHOW_CONTEXT_MENU__",
       "suggested_key": {
         "chromeos": "Search+Ctrl+Space"
       }
     }
 {% endif %}
   },
   "options_page": "chromevox/background/options.html",
   "default_locale": "en"
 }