Don't lose service instances after gateway/broker restart

After a gateway/broker restart it is unable to rebuild its catalog from the cloud controller.
As a consequence you will not be able to bind to existing services. 
Services which where bind before the restart keep functioning as normal.

The problem could be traced back to the [addition of a type field for service instances](https://github.com/cloudfoundry/cloud_controller_ng/commit/a142df242fbb2ef2108704fde4caec0fd8b2fd83).
This `type` field is not expected by the catalog manager and as a result it decides to skip the instance.