Merge branch '2.6' into 2.7

* 2.6: (21 commits)
  bumped Symfony version to 2.6.8
  updated VERSION for 2.6.7
  updated CHANGELOG for 2.6.7
  bumped Symfony version to 2.3.29
  updated VERSION for 2.3.28
  update CONTRIBUTORS for 2.3.28
  updated CHANGELOG for 2.3.28
  [Debug] Fixed ClassNotFoundFatalErrorHandlerTest
  [SecurityBundle] use access decision constants in config
  [SecurityBundle] use session auth constants in config
  PhpDoc fix in AbstractRememberMeServices
  [Filesystem] Simplified an if statement
  [SecurityBundle] Use Enum Nodes Instead Of Scalar
  [Debug 2.3] Fix test for PHP7
  [HttpKernel] Check if "symfony/proxy-manager-bridge" package is installed
  [Translation] simplify getMessages.
  [Framework][Translation] added test for debug command.
  Run tests on hhvm instead of hhvm-nightly
  Use HTTPS in README and some other fixes
  add more entropy to generated classnames
  ...

Conflicts:
	.travis.yml
	src/Symfony/Component/HttpKernel/Kernel.php

Author: fabpot

DependencyInjection/MainConfiguration.php

@@ -16,6 +16,7 @@
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
 use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
 use Symfony\Component\Config\Definition\ConfigurationInterface;
+use Symfony\Component\Security\Http\Session\SessionAuthenticationStrategy;
 
 /**
  * This class contains the configuration information.
@@ -60,14 +61,20 @@ public function getConfigTreeBuilder()
         $rootNode
             ->children()
                 ->scalarNode('access_denied_url')->defaultNull()->example('/foo/error403')->end()
-                ->scalarNode('session_fixation_strategy')->cannotBeEmpty()->info('strategy can be: none, migrate, invalidate')->defaultValue('migrate')->end()
+                ->enumNode('session_fixation_strategy')
+                    ->values(array(SessionAuthenticationStrategy::NONE, SessionAuthenticationStrategy::MIGRATE, SessionAuthenticationStrategy::INVALIDATE))
+                    ->defaultValue(SessionAuthenticationStrategy::MIGRATE)
+                ->end()
                 ->booleanNode('hide_user_not_found')->defaultTrue()->end()
                 ->booleanNode('always_authenticate_before_granting')->defaultFalse()->end()
                 ->booleanNode('erase_credentials')->defaultTrue()->end()
                 ->arrayNode('access_decision_manager')
                     ->addDefaultsIfNotSet()
                     ->children()
-                        ->scalarNode('strategy')->defaultValue(AccessDecisionManager::STRATEGY_AFFIRMATIVE)->end()
+                        ->enumNode('strategy')
+                            ->values(array(AccessDecisionManager::STRATEGY_AFFIRMATIVE, AccessDecisionManager::STRATEGY_CONSENSUS, AccessDecisionManager::STRATEGY_UNANIMOUS))
+                            ->defaultValue(AccessDecisionManager::STRATEGY_AFFIRMATIVE)
+                        ->end()
                         ->booleanNode('allow_if_all_abstain')->defaultFalse()->end()
                         ->booleanNode('allow_if_equal_granted_denied')->defaultTrue()->end()
                     ->end()