[DependencyInjection] Removed unreachable code

| Q             | A
| ------------- | ---
| Bug fix?      | not really
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

According to undefined $e, this is an unreachable code. As I can see, circular references are handled by parent method.