Comment 8 for bug 1798618

I tested this on cosmic using the well written test case from the bug description and confirm that the fix works.

bdmurray@clean-cosmic-amd64:~$ tail -n1 /etc/update-manager/release-upgrades
Prompt=lts
bdmurray@clean-cosmic-amd64:~$ apt-cache policy ubuntu-release-upgrader-core
ubuntu-release-upgrader-core:
  Installed: 1:18.10.11.4
  Candidate: 1:18.10.11.4
  Version table:
 *** 1:18.10.11.4 500
        500 http://192.168.10.7/ubuntu cosmic-proposed/main amd64 Packages
        500 http://192.168.10.7/ubuntu cosmic-proposed/main i386 Packages
        100 /var/lib/dpkg/status
     1:18.10.11.3 500
        500 http://192.168.10.7/ubuntu cosmic-updates/main amd64 Packages
        500 http://192.168.10.7/ubuntu cosmic-updates/main i386 Packages
     1:18.10.11 500
        500 http://192.168.10.7/ubuntu cosmic/main amd64 Packages
        500 http://192.168.10.7/ubuntu cosmic/main i386 Packages
bdmurray@clean-cosmic-amd64:~$ do-release-upgrade -d
Checking for a new Ubuntu release
There is no development version of an LTS available.
To upgrade to the latest non-LTS develoment release
set Prompt=normal in /etc/update-manager/release-upgrades.

Although the error message does not appear to be so well written as it is missing a 'p'. I'm still setting it to verification-done though.