To uninstall ubuntu-release-upgrader-qt just follow these instructions.
/ubuntu/vivid/universe///install/index.html manage release upgrades Ubuntu 15.04 universe/admin 1:15.04.14
sudo apt-get remove ubuntu-release-upgrader-qt
Which will remove just the ubuntu-release-upgrader-qt package itself.
sudo apt-get remove --auto-remove ubuntu-release-upgrader-qt
This will remove the ubuntu-release-upgrader-qt package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for ubuntu-release-upgrader-qt then this will work.
sudo apt-get purge ubuntu-release-upgrader-qt
Or similarly, like this ubuntu-release-upgrader-qt
sudo apt-get purge --auto-remove ubuntu-release-upgrader-qt
|Description||manage release upgrades|