Dropping Ubuntu/trusty builds for Foreman 1.16


following the discussion[1] about desupporting Ruby 2.0 for Foreman
core, Foreman nightly packages for Ubuntu/trusty are not being built
anymore since today and there will be no 1.16 release for Ubuntu/trusty.
This also affects Proxy and Installer packages.

1.15 packages will still receive updates, but it's strongly advised to
update to Ubuntu/xenial, which is supported since Foreman 1.12.

[1] https://groups.google.com/forum/#!topic/foreman-dev/lOGOBzFAybI


··· -- Michael Moll