Docker sync.yml does not match with default URL in opengrok-sync

[vladak]

When running opengrok-sync with the docker/sync.yml without -U:

RESTful command {'command': ['%URL%api/v1/messages', 'POST', {'messageLevel': 'warning', 'duration': 'PT1H', 'tags': ['%PROJECT%'], 'text': 'resync + reindex in progress'}]} failed: 404 Client Error:  for url: http://localhost:8080/sourceapi/v1/messages

The sync.yml contains:

- command:
  - '%URL%api/v1/messages'
  - POST
  - messageLevel: warning
    duration: PT1H
    tags: ['%PROJECT%']
    text: resync + reindex in progress

That's because the start.py Docker script tries hard to have the URL ending with slash. The URL defaults in the Python tools should be united with the Docker script (change either the script or the tools).