knotc -w doesn't work as expected

Problem

knotc -w stop doesn't wait for the executable to terminate when issued remotely.

Solution

The removal of start/restart have made this flag obsolete so I suggest to remove it. It is not a problem when running in managed mode, as it should be stopped using signals preferrably.

The reason behind this is, that even if we delay reply to the stop command, there will still be a short period when the server would be running requiring some sort of grace time and estimates.