removing rack controller from region controller doesn't remove it from maas db

[Michał Ajduk]

When after removing rack controller from region controller (when the two are collocated), the operation does not remove it from maas db; maas always tries to use it', 'maas-rack command is being executed by region controller, even though there's no rack controller' and 'ip already exists':

Eg:
  File "/usr/lib/python3/dist-packages/provisioningserver/utils/fs.py", line 281, in sudo_write_file
    raise ExternalProcessError(proc.returncode, command, stderr)
provisioningserver.utils.shell.ExternalProcessError: Command `maas-rack atomic-write --filename /etc/ntp/maas.conf --mode 0644` returned non-zero exit status 1:
None

Moreover the server is still remorted as 'Region and rack controller'.

dtadmin@ba0b1a-mgm231maasregion-sk:~$ dpkg -l '*maas*'|cat
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-===============================-==============================-============-=============================================
un maas <none> <none> (no description available)
ii maas-cli 2.1.3+bzr5573-0ubuntu1~16.04.1 all MAAS client and command-line interface
ii maas-common 2.1.3+bzr5573-0ubuntu1~16.04.1 all MAAS server common files
ii maas-dhcp 2.1.3+bzr5573-0ubuntu1~16.04.1 all MAAS DHCP server
ii maas-dns 2.1.3+bzr5573-0ubuntu1~16.04.1 all MAAS DNS server
ii maas-proxy 2.1.3+bzr5573-0ubuntu1~16.04.1 all MAAS Caching Proxy
ii maas-region-api 2.1.3+bzr5573-0ubuntu1~16.04.1 all Region controller API service for MAAS
ii maas-region-controller 2.1.3+bzr5573-0ubuntu1~16.04.1 all Region Controller for MAAS
un maas-region-controller-min <none> <none> (no description available)
un python-django-maas <none> <none> (no description available)
un python-maas-client <none> <none> (no description available)
ii python3-django-maas 2.1.3+bzr5573-0ubuntu1~16.04.1 all MAAS server Django web framework (Python 3)
ii python3-maas-client 2.1.3+bzr5573-0ubuntu1~16.04.1 all MAAS python API client (Python 3)
ii python3-maas-provisioningserver 2.1.3+bzr5573-0ubuntu1~16.04.1 all MAAS server provisioning libraries (Python 3)

[Peter Matulis (petermatulis)]

@Andres, how is this bug a duplicate of bug #1650481 ?