Merge branch '2.3' into 2.6

* 2.3:
  Minor fixes
  Towards 100% HHVM compat
  trigger event with right user (add test)
  [Security] Initialize SwitchUserEvent::targetUser on attemptExitUser
  [Form] Fixed: Data mappers always receive forms indexed by their names

Conflicts:
	src/Symfony/Component/Debug/Tests/ErrorHandlerTest.php
	src/Symfony/Component/Filesystem/Filesystem.php
	src/Symfony/Component/Process/Tests/AbstractProcessTest.php

Author: nicolas-grekas

Tests/Generator/Dumper/PhpGeneratorDumperTest.php

@@ -39,7 +39,7 @@ protected function setUp()
 
         $this->routeCollection = new RouteCollection();
         $this->generatorDumper = new PhpGeneratorDumper($this->routeCollection);
-        $this->testTmpFilepath = sys_get_temp_dir().DIRECTORY_SEPARATOR.'php_generator.php';
+        $this->testTmpFilepath = sys_get_temp_dir().DIRECTORY_SEPARATOR.'php_generator.'.$this->getName().'.php';
         @unlink($this->testTmpFilepath);
     }