Missing dependency to zend-form in zend-mvc

[tux-rampage]

See Issue #6162 (I cannot reopen this one)

This dependency is not in the skeleton app, but hardcoded in Zend\Mvc\Service\ServiceListenerFactory.

So there are two options:

1. Add a dependency to zend-form to the composer.json of zend-mvc
2. Change the ServiceListenerFactory to check for the existence of Zend\Form\FormAbstractServiceFactory before adding it as abstract factory.

I can offer a PR for option 2 if this is preferred.

[tux-rampage]

Dependency was introduced in commit eaa7874

[Ocramius]

@tux-rampage fixed, thanks