Incorrect assertion for binding requests and accepts_incomplete query param

[jeremyrickard]

OSB Spec has the following to say about the accepts_incomplete param:

Note: Asynchronous operations are currently supported only for provision, update, and deprovision.
For a broker to return an asynchronous response, the query parameter accepts_incomplete=true MUST be included the request. If the parameter is not included or is set to false, and the broker cannot fulfill the request synchronously (guaranteeing that the operation is complete on response), then the broker SHOULD reject the request with the status code 422 Unprocessable Entity and the following body:

As indicated above, binding operations currently should not handle the accept_incomplete param and should therefore not fail with the 422 Unprocessable Entity status.

This check should probably be removed to be in alignment with the specification (as it's not supported, should the asynch option even exist for defining bindings in the test configuration?).