BZ #1103271 - puppet modules need to handle missing openstack-selinux gracefully

https://bugzilla.redhat.com/show_bug.cgi?id=1103271

Do not install openstack-selinux on el7, just selinux-policy.
Merge pull request #241 from cwolferh/icehouse_package_fixes

openstack-selinux not available in el7 so don't try to install it