[WebProfilerBundle] Avoid missing method when using __invoke on a controller

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

2.6 added support for using `__invoke` on controllers, but the profiler toolbar still expects a method name, leading to:

![image](https://cloud.githubusercontent.com/assets/1784740/5412993/4553c4da-820a-11e4-899c-50ef9f330cdd.png)

This PR changes it to only include the method section/double dots if the method name is included (and the `link` is moved to the class name).