Description of problem:
When provisioning a RHEL on Power system via Satellite 6, the provisioning logic selects the incorrect server.filename for bootp/dhcp requests.  

Version-Release number of selected component (if applicable):
Capsule:
foreman-debug-1.11.0.53-1.el7sat.noarch
foreman-discovery-image-3.1.1-16.el7sat.noarch
foreman-installer-1.11.0.10-1.el7sat.noarch
foreman-installer-katello-3.0.0.57-1.el7sat.noarch
foreman-proxy-1.11.0.6-1.el7sat.noarch
foreman-selinux-1.11.0.2-1.el7sat.noarch
katello-capsule-3.0.0-12.el7sat.noarch
satellite-capsule-6.2.2-1.1.el7sat.noarch
tfm-rubygem-hammer_cli_foreman-0.5.1.9-1.el7sat.noarch
tfm-rubygem-hammer_cli_foreman_discovery-0.0.2.3-1.el7sat.noarch


How reproducible:
every time

Steps to Reproduce:
1. Configure a new host via Hosts > All Hosts > New
2. Select Redhat 7.2 ppc64 as the Operating System on the Operating System Tab
3. Configure the primary interface as DHCP
4. Submit the new Host

Actual results:
Host is configured with default x86_64 pxelinux.0 image for supersede server.filename
host client.example.com {
  dynamic;
  hardware ethernet 9e:32:2e:5d:74:03;
  fixed-address 192.168.224.10;
        supersede server.filename = "pxelinux.0";
        supersede server.next-server = ac:19:c5:15;


Expected results:
Host is configured with default PPC64 core.elf image for supersede server.filename
host client.example.com {
  dynamic;
  hardware ethernet 9e:32:2e:5d:74:03;
  fixed-address 192.168.224.101;
        supersede server.filename = "boot/grub2/powerpc-ieee1275/core.elf";
        supersede server.next-server = ac:19:c5:15;

Additional info:
It appears that the entire boot infrastructure hasn't been properly configured in SAtellite 6 for RHEL on Power provisioning.