bug symfony#3709 [Components][Security] Fix symfony#3708 (bicpi)

This PR was merged into the 2.3 branch.

Discussion
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[Components][Security] Fix symfony#3708

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | symfony#3708

Commits
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da025b1 [Components][Security] Fix symfony#3708

Author: weaverryan

components/security/authorization.rst

@@ -142,7 +142,7 @@ method::
 
     $roleVoter = new RoleVoter('ROLE_');
 
-    $roleVoter->vote($token, $object, 'ROLE_ADMIN');
+    $roleVoter->vote($token, $object, array('ROLE_ADMIN'));
 
 RoleHierarchyVoter
 ~~~~~~~~~~~~~~~~~~