Update Service Definitions to new setFactory methods

Currently trying to use the extension with post Symfony 2.6 dependencies breaks it due to the error:

The error "Symfony\Component\DependencyInjection\Definition::setFactoryService(vipsoft.code_coverage.driver.factory) is deprecated since version 2.
6 and will be removed in 3.0. Use Definition::setFactory() instead."

It would be nice if you could update the services.xml to use the updated definitions and support Symfony 2.6+. I am not familiar with XML definitions to issue a PR myself.

[ek9]

In case you are coming back to this in the future, I have fixed it in a forked version of the package, changes in the commit: leanphp/behat-code-coverage@371c44c#diff-09af2b221d2475b568160a53310abe2aL63
(I am maintaining the fork to keep compatibility with both versions of Symfony until 2.8 LTS is maintained, so I kept support for older service definitions too). Hope this is any helpful for those looking for a fix (or you can alternatively give it a go to a leanphp/behat-code-coverage (which is a fork of this)).