Validate consumes contains a valid mime-type for file based parameters

[analogue]

Implement this validation in ssv:

def add_file(param, value, request):
    """Add a parameter of type 'file' to the given request.

    :type param: :class;`bravado.mapping.param.Param`
    :param value: The raw content of the file to be uploaded
    :type request: dict
    """
    if request.get('files') is None:
        # support multiple files by default by setting to an empty array
        request['files'] = []

        # The http client should take care of setting the content-type header
        # to 'multipart/form-data'. Just verify that the swagger spec is
        # conformant
        expected_mime_type = 'multipart/form-data'
        if expected_mime_type not in param.op.consumes:
            raise SwaggerMappingError((
                "Mime-type '{0}' not found in list of supported mime-types for "
                "parameter '{1}' on operation '{2}': {3}").format(
                    expected_mime_type,
                    param.name,
                    param.op.operation_id,
                    param.op.consumes
                ))

    file_tuple = ('file', (param.name, value))
    request['files'].append(file_tuple)