[Openshift] Delete Service Instance based on a Service Class that uses dots in its name

Issue

• It is not possible to delete a service instance based on a service class that uses dots in its name

$ oc describe serviceinstance/sevinst5|grep 'Cluster Service Class External Name'
  Cluster Service Class External Name:  service-7.1-basic-authentication-example-starter

• Deleting this service instance will apparently succeed:

$ oc delete serviceinstance sevinst6
serviceinstance "sevinst6" deleted

• Listing the service instances shows that the "deleted" one is still there

$ oc get serviceinstance
NAME       AGE
sevinst6   23h

• Editing the service instance and deleting the finalizers lines will produce an error:

 spec.clusterServiceClassExternalName: Invalid value: "service-7.1-basic-authentication-example-starter": [-a-zA-Z0-9]+ (regex used for validation is 'service-name-40d-0983-1b89')