[ticket/13407] Update Symfony to 2.7.*@dev
* Nicofuma/ticket/13407:
[ticket/13407] Update composer.lock file
[ticket/13407] Bump minimal version to php 5.3.9
[ticket/13407] Introduce a request_stack service
[ticket/13407] Remove the last occurence of pattern in routing files
[ticket/13407] Update Symfony to 2.7.*@dev