fix ocramius/proxy-manager dependency version

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

Revert #12776 for Symfony 2.5 and higher to make builds pass again.