Update sudoers.pp

Initial support for rhel 7.0. Code "'set target[1]/sudo_provider ipa'," is not necessary on rhel 7 (according to rhel 7 documentation)
Actually this is better, because we want it to work on CentOS and other clones too:

```
elseif ($::operatingsystem != "Fedora" and versioncmp($::operatingsystemrelease, '7.0') >= 0) {
```