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

I believe i tested it through and through but if someone can give it a run too that would be nice. I'm a bit worried that Scott reported problems that i couldn't replicate. I tested with these package versions:
http://fpaste.org/97049/98453705/