motd.tail isn't a thing in Ubuntu 14.04 and beyond. The simplest way to keep it working is to add a file to /etc/update-motd.d that displays /etc/motd.tail
@e0d there was some thought that your xenial branch had a fix for this, but I didn't see it.
Make sure that the following steps are done before merging
BTW, if this technique rubs you the wrong way, I can do it differently.
motd.tail support for Xenial
Verified here: feanil.sandbox.edx.org