Load body_listener before "security.firewall"

As of Symfony2.1, the security.firewall is loaded with priority 8 (earlier 64).

To use the body_listener for login-services, it has to be loaded before the firewall.

Please add a priority higher than 8. I just took 10 ...
Merge pull request #593 from SimonSimCity/patch-1

Load body_listener before "security.firewall"
Merge branch 'FOS-master/master'