Refs #6360 - enable pulp_manage_puppet selinux boolean

Tested with ad-hoc puppet command:

```
puppet apply -e "  exec {'selinux_pulp_manage_puppet':
    command => 'semanage boolean -m --on pulp_manage_puppet',
    path    => '/sbin:/usr/sbin:/bin:/usr/bin',
    onlyif  => 'getsebool pulp_manage_puppet | grep off',
  }
" -v --debug
```

Please confirm that this gets called AFTER pulp (thus pulp-selinux) is
installed. If not, I need to add a require. But I think it should be
fine. Double-check.

It works fine even when this flag is not available (it skips).