The systemctl in Debian unstable fails when trying to disable a removed
service. The manpage do not mention a switch to change this behaviour.
But it says:
Note that this operation creates only the suggested symlinks for
the units. While this command is the recommended way to manipulate
the unit configuration directory, the administrator is free to make
additional changes manually by placing or removing symlinks in the
directory.
So a simple rm should be fine.
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