Default validation message translation fix.

Add 'validators' for $translationDomain. Detailed discussion https://github.com/fabpot/Silex/pull/641
Merge branch '2.2'

* 2.2: (26 commits)
  [FrameworkBundle] Fixes invalid serialized objects in cache
  remove dead code in yaml component
  Fixed typo in UPGRADE-2.2
  fixed typo
  RedisProfilerStorage wrong db-number/index-number selected
  [DependencyInjection] added a test for the previous merge (refs #7261)
  Unset loading[$id] in ContainerBuilder on exception
  Default validation message translation fix.
  remove() should not use deprecated getParent() so it does not trigger deprecation internally
  adjust routing tests to not use prefix in addCollection
  add test for uniqueness of resources
  added tests for addDefaults, addRequirements, addOptions
  adjust RouteCollectionTest for the addCollection change and refactor the tests to only skip the part that really needs the config component
  added tests for remove() that wasnt covered yet and special route name
  refactor interator test that was still assuming a tree
  adjust tests to no use addPrefix with options
  adjusted tests to not use RouteCollection::getPrefix
  [Routing] trigger deprecation warning for deprecated features that will be removed in 2.3
  [Console] fixed StringInput binding
  [Console] added string input test
  ...