Fix bug in query parameter validation

### What is the problem / feature ?

Query parameter validation was failing on an edge case.
- query parameters present in the request and the operation definition which don't overlap.

### How did it get fixed / implemented ?

fixed the logic.

### How can someone test / see it ?

Validate a request with query parameters against an operation with other parameters.


*Here is a cute animal picture for your troubles...*

![christmas-animals-002](https://cloud.githubusercontent.com/assets/824194/5482223/47087988-861a-11e4-9adf-dda7eef69c94.jpg)