Error rendering iot-agent lwm2m template

[c0c0n3]

The iot-agent chart can't be generated when service.agentType is set to: lwm2m. It stops with a rendering error.

To reproduce:

1. Edit charts/iot-agent/values.yaml to set agentType: lwm2m in the service stanza.
2. Run helm install charts/iot-agent --debug --dry-run

You should see an error similar to:

[debug] CHART PATH: /Users/andrea/github/orchestracities.charts/charts/iot-agent

Error: render error in "iot-agent/templates/configmap-lwm2m.yaml":
  template: iot-agent/templates/configmap-lwm2m.yaml:17:29:
    executing "iot-agent/templates/configmap-lwm2m.yaml" at <.Values.lwm2m.logLevel>:
      nil pointer evaluating interface {}.logLevel

Tested with Helm client version v2.13.1 and server v2.14.1.