[Security] Delete old session on auth strategy migrate
Merge branch '2.3' into 2.5

* 2.3:
  [Config] adds missing « use » statement for InvalidTypeException type hint in documentation.
  [Config] fixes broken unit test on ArrayNode class.
  fixed CS
  [Security] Delete old session on auth strategy migrate
  update required minimum TwigBridge version
  Very minor grammar fix in error message
  [Tests] Silenced all deprecations in tests for 2.3
  BinaryFileResponse - add missing newline
  fixed CS
  add a limit and a test to FlattenExceptionTest.
  CS: There should be no empty lines following phpdocs
  [FrameworkBundle] fix cache:clear command
  [2.3] Docblocks should not be followed by a blank line
  Fix return phpdoc
  [PropertyAccess] Added test to verify #5775 is fixed

Conflicts:
	src/Symfony/Bundle/TwigBundle/composer.json
	src/Symfony/Component/PropertyAccess/Tests/PropertyAccessorTest.php
	src/Symfony/Component/Security/Core/Tests/Validator/Constraints/UserPasswordValidatorTest.php