Fix tests for Symfony 2.2

In the file web testcase Symfony 2.3 code was used for the forms. Let's see if travis now runs successful.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A