Don't filter env vars in controller

Depending on isNew can result in rerendering templates in some cases, which will
also create a new object controller, which in turn will reset isEditing value.

app/controllers/env-vars.coffee

@@ -1,6 +1,6 @@
 `import Ember from 'ember'`
 
 Controller = Ember.ArrayController.extend
-  vars: Ember.computed.filterBy('model', 'isNew', false)
+  vars: Ember.computed.alias('model')
 
 `export default Controller`

app/templates/env-vars.hbs

@@ -2,6 +2,7 @@
 
 <ul class="env-vars">
   {{#each vars itemController="envVar"}}
+    {{#unless isNew}}
       <li class="env-var">
         {{#if isEditing}}
           {{partial 'env_vars/form'}}
@@ -14,5 +15,6 @@
           <span {{bind-attr class=":value :value-display public::secure"}}>{{value}}</span>
         {{/if}}
       </li>
+    {{/unless}}
   {{/each}}
 </ul>