[SecurityBundle] Changed environment to something unique.

If you run functional tests from different bundles you it will cause a redeclare error
because the DIC appKernel name is not unique.

src/Symfony/Bundle/SecurityBundle/Tests/Functional/WebTestCase.php

@@ -59,7 +59,7 @@ class WebTestCase extends BaseWebTestCase
         return new $class(
             $options['test_case'],
             isset($options['root_config']) ? $options['root_config'] : 'config.yml',
-            isset($options['environment']) ? $options['environment'] : 'test',
+            isset($options['environment']) ? $options['environment'] : 'securitybundletest',
             isset($options['debug']) ? $options['debug'] : true
         );
     }