Cleanup annotations

Wskdebug sets `wskdebug` annotation and uses it to detect current deployment status of agent - https://github.com/apache/openwhisk-wskdebug/blob/master/src/agentmgr.js#L530

During the cleanup phase, wskdebug will delete all agents and restore the original action, but this annotation is not deleted so wskdebug will prevent all consequent runs thinking it's already running.