Add an informative log message when creating PTS without a container name

[jsenko]

The Kubernetes client error might be confusing:

Caused by: io.fabric8.kubernetes.client.KubernetesClientException: Failure executing: POST at: [https://172.30.0.1:443/apis/apps/v1/namespaces/case04189883/deployments](https://172.30.0.1/apis/apps/v1/namespaces/case04189883/deployments). Message: Deployment.apps "simple-app-deployment" is invalid: [spec.template.spec.containers[0].name: Required value, spec.template.spec.containers[0].image: Required value]. Received status: Status(apiVersion=v1, code=422, details=StatusDetails(causes=[StatusCause(field=spec.template.spec.containers[0].name, message=Required value, reason=FieldValueRequired, additionalProperties={}), StatusCause(field=spec.template.spec.containers[0].image, message=Required value, reason=FieldValueRequired, additionalProperties={})], group=apps, kind=Deployment, name=simple-app-deployment, retryAfterSeconds=null, uid=null, additionalProperties={}), kind=Status, message=Deployment.apps "simple-app-deployment" is invalid: [spec.template.spec.containers[0].name: Required value, spec.template.spec.containers[0].image: Required value], metadata=ListMeta(_continue=null, remainingItemCount=null, resourceVersion=null, selfLink=null, additionalProperties={}), reason=Invalid, status=Failure, additionalProperties={}).
        at io.fabric8.kubernetes.client.dsl.internal.OperationSupport.requestFailure(OperationSupport.java:660)