Loosing process Handlers in node.py

[bekiralti]

The method Node.start() starts a new villas-node process. However if it is run twice, the first process-handler, which got saved in self.child gets overwritten by the second process handler.

The command in question:

self.child = subprocess.Popen(
    [self.executable, self.config_file.name],
    stdout=self.log,
    stderr=self.log,
)

If necessary I can provide example configs for villas-controller to recreate this issue, providing it now would have bloated up my initial post :D