fix key observer test

spec/observers/key_observer_spec.rb

@@ -2,12 +2,7 @@ require 'spec_helper'
 describe KeyObserver do
   before do
-    @key = double('Key',
-      shell_id: 'key-32',
-      key: '== a vaild ssh key',
-      projects: [],
-      is_deploy_key: false
-    )
+    @key = create(:personal_key)
     @observer = KeyObserver.instance
   end