This bug was fixed in the package xorg - 1:7.7+19ubuntu5
--------------- xorg (1:7.7+19ubuntu5) bionic; urgency=medium
* Cleanup upstart Xsession.d files, when upstart is removed, but not purged, and thus breaking graphical login after upgrades. LP: #1749199
-- Dimitri John Ledkov <email address hidden> Thu, 22 Feb 2018 16:43:18 +0000
This bug was fixed in the package xorg - 1:7.7+19ubuntu5
---------------
xorg (1:7.7+19ubuntu5) bionic; urgency=medium
* Cleanup upstart Xsession.d files, when upstart is removed, but not
purged, and thus breaking graphical login after upgrades. LP: #1749199
-- Dimitri John Ledkov <email address hidden> Thu, 22 Feb 2018 16:43:18 +0000