Description of problem:
after adding automation-broker-apb's registry to asb,  service catalog can not fetch the spec to clusterserviceclass.
asb log:

level=error msg="not adding spec au-automation-broker-apb to list of services due to error transforming to service - Could not find the parameter type for: "

Version-Release number of selected component (if applicable):
asb: 1.3.8
automation-broker-apb: dockerhub/latest( or v3.11)

How reproducible:
always

Steps to Reproduce:
1. add registry to asb
  - type: dockerhub
    name: au
    url:  https://registry.hub.docker.com
    org:  automationbroker
    tag: v3.11
    white_list:
      - ".*-apb$"

2. restart asb pod and relist service catalog, check bundles and clusterserviceclass
asb log:
level=error msg="not adding spec au-automation-broker-apb to list of services due to error transforming to service - Could not find the parameter type for: "

# oc get bundles -o=custom-columns=NAME:.metadata.name,FQ\ NAME:.spec.fq_name -n openshift-ansible-service-broker
NAME                               FQ NAME
0300d1ae1841c23a9df0a179ad0605fd   brew-mariadb-apb
0e5dbb6592fec99057f94fbb095ec558   brew-mediawiki-apb
48749329dd289591e11ba737f15fc71b   brew-postgresql-apb
b0c2f33e4b1cc50667294b02a95ff2e9   au-automation-broker-apb
bd8dff760b959264f3ab38d42ba5e7a8   brew-mysql-apb

# oc get clusterserviceclass -o=custom-columns=NAME:.metadata.name,EXTERNAL\ NAME:.spec.externalName
NAME                               EXTERNAL NAME
0300d1ae1841c23a9df0a179ad0605fd   brew-mariadb-apb
0e5dbb6592fec99057f94fbb095ec558   brew-mediawiki-apb
48749329dd289591e11ba737f15fc71b   brew-postgresql-apb
bd8dff760b959264f3ab38d42ba5e7a8   brew-mysql-apb

3.

Actual results:
autoamtion-broker-apb not added to clusterserviceclass 
# oc get bundle b0c2f33e4b1cc50667294b02a95ff2e9 -o yaml -n openshift-ansible-service-broker
apiVersion: automationbroker.io/v1alpha1
kind: Bundle
metadata:
  creationTimestamp: 2018-08-14T05:55:55Z
  generation: 1
  name: b0c2f33e4b1cc50667294b02a95ff2e9
  namespace: openshift-ansible-service-broker
  resourceVersion: "35194"
  selfLink: /apis/automationbroker.io/v1alpha1/namespaces/openshift-ansible-service-broker/bundles/b0c2f33e4b1cc50667294b02a95ff2e9
  uid: b55177ed-9f86-11e8-bdef-fa163e2eb7b5
spec:
  Alpha: "null"
  async: optional
  bindable: false
  delete: false
  description: deploys automation broker for the service-catalog
  fq_name: au-automation-broker-apb
  image: docker.io/automationbroker/automation-broker-apb:v3.11
  metadata: '{"dependencies":[],"displayName":"Automation Broker (APB)","longDescription":"An
    APB for managing the automation broker in a cluster","providerDisplayName":"Red
    Hat, Inc."}'
  plans:
  - bindable: false
    description: Manage the automation broker in a cluster
    free: false
    id: 45f0bb71695167077e62362420415e0f
    metadata: '{"cost":"$0.00","displayName":"Default","longDescription":"This plan
      deploys the automation broker"}'
    name: main
    parameters:
    - default: '{"default":"automation-broker"}'
      deprecatedMaxLength: 0
      description: ""
      maxLength: 0
      name: broker_name
      required: false
      title: Name of the broker
      type: string
      updatable: false
    - default: '{"default":"automation-broker"}'
      deprecatedMaxLength: 0
      description: ""
      maxLength: 0
      name: broker_namespace
      required: false
      title: Namespace of the broker
      type: string
      updatable: false
    - default: '{"default":"ansibleplaybookbundle/origin-ansible-service-broker:latest"}'
      deprecatedMaxLength: 0
      description: ""
      maxLength: 0
      name: broker_image
      required: false
      title: Container image for the broker
      type: string
      updatable: false
    - default: '{"default":"ansible-service-broker"}'
      deprecatedMaxLength: 0
      description: Name for the clusterservicebroker object
      maxLength: 0
      name: cluster_service_broker_name
      required: false
      title: Cluster Service Broker Resource Name
      type: ""
      updatable: false
  runtime: 2
  version: "1.0"
status:
  status: ""

Expected results:
automation-broker-apb added to service class.

Additional info:
after update the paramater type from "" to string , it can be added to service class.