[Yaml] Reduce our class completion scope because of orocrm plugin

[Haehnchen]

https://github.com/orocrm/oro-phpstorm-plugin

Symfony2 plugin adds suggestions for all php classes when yml key is "class", but this behaviour is undesirable from my plugin point of view. I would like to add some specific suggestions for "class" key in certain files and cerrtain places in those files.