Proper typehints in ServiceLocatorAwareTrait

The typehints are wrong. Either import the ServiceLocator class, or, what's the right thing, declare the types as what they are: ServiceLocatorInterface.
Merge branch 'patch-1' of https://github.com/demonkoryu/zf2 into demonkoryu-patch-1
Merge branch 'demonkoryu-patch-1'