Merge branch '2.3' into 2.4

* 2.3:
  [Bridge][Twig] Replace deprecated features
  [HttpFoundation] fix switch statement
  [Doctrine Bridge] fix DBAL session handler according to PdoSessionHandler
  fixed previous merge
  Added phpdoc for Cache-Control directives methods
  Remove undefined variable $e
  bumped Symfony version to 2.3.17
  Fix a parameter name in a test
  updated VERSION for 2.3.16
  update CONTRIBUTORS for 2.3.16
  updated CHANGELOG for 2.3.16
  [HttpFoundation] use different approach for duplicate keys in postgres, fix merge for sqlsrv and oracle

Conflicts:
	src/Symfony/Component/DependencyInjection/ContainerBuilder.php
	src/Symfony/Component/HttpKernel/Kernel.php

Author: fabpot

Tests/Constraints/NotBlankValidatorTest.php

@@ -35,12 +35,12 @@ protected function tearDown()
     /**
      * @dataProvider getValidValues
      */
-    public function testValidValues($date)
+    public function testValidValues($value)
     {
         $this->context->expects($this->never())
             ->method('addViolation');
 
-        $this->validator->validate($date, new NotBlank());
+        $this->validator->validate($value, new NotBlank());
     }
 
     public function getValidValues()