Fixed metadata serialization
Merge branch '2.0' into 2.1

* 2.0:
  Fixed metadata serialization
[Validator] fixed metadata serialization
added trusted hosts check
Merge branch '2.0' into 2.1

* 2.0:
  added trusted hosts check

Conflicts:
	src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
	src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php
	src/Symfony/Component/HttpFoundation/Tests/RequestTest.php
updated CHANGELOG for 2.1.12
updated VERSION for 2.1.12