Fix integration with OCHamcrest

Note using id<KWGenericMatching> breaks OCHamcrest integration with Kiwi and cause Xcode
warning: sending 'id<HCMatcher>' to parameter of incompatible type 'id<KWGenericMatching>'
as Hamcrest has own HCMatcher protocol and unaware of KWGenericMatching protocol.

Passing generic id object works.

See https://github.com/hamcrest/OCHamcrest for definition of HCMatcher protocol