clean up unused currentEnv and env

Author: mansona

ember_debug/vendor/startup-wrapper.js

@@ -11,15 +11,11 @@ let Ember;
  Also responsible for sending the first tree.
  **/
 /*eslint prefer-spread: 0 */
-/* globals adapter, env */
+/* globals adapter */
 var currentAdapter = 'basic';
 if (typeof adapter !== 'undefined') {
   currentAdapter = adapter;
 }
-var currentEnv = 'production';
-if (typeof env !== 'undefined') {
-  currentEnv = env;
-}
 
 // @formatter:off
 var EMBER_VERSIONS_SUPPORTED = {{EMBER_VERSIONS_SUPPORTED}};