Update foreman_server.sh to support Foreman 1.5 release

- Remove 'include passenger' from the install manifest, as it appears
  this was never needed, and actually causes a problem with 1.5
- Change the location of seeds.rb, since Foreman is now using the "real"
  seeds.rb, and makes use of a seeds.d drop dir.
- Change Ruby code using Facter to Facter.value() syntax

Co-Authored-By: Jiri Stransky <jistr@redhat.com>
Merge pull request #193 from jistr/foreman-1.5-compat

Update foreman_server.sh to support Foreman 1.5 release