Added support for RHEL and did some syntax cleaning

Assume that "RedHat" also works where "CentOS" does.

user/manifests/init.pp

@@ -6,13 +6,13 @@ class user::system {
         ensure => directory,
         mode   => "0755",
         owner  => "root",
-        group  => $operatingsystem ? {
+        group  => $::operatingsystem ? {
             "openbsd" => "wheel",
             default   => "root",
         },
     }
 
-    if $operatingsystem == "ubuntu" {
+    if $::operatingsystem == "ubuntu" {
         file { "/sbin/nologin":
             ensure => link,
             target => "/usr/sbin/nologin",
@@ -64,7 +64,7 @@ class user::system {
         gid     => 802,
         comment => "Service Jabber",
         home    => "/var/lib/ejabberd",
-        shell   => $operatingsystem ? {
+        shell   => $::operatingsystem ? {
             "ubuntu" => "/bin/sh",
             default  => "/sbin/nologin",
         },
@@ -261,7 +261,7 @@ define user::newuser($uid, $gid, $comment, $home, $shell, $groups=undef, $requir
         shell   => $shell,
         groups  => $groups,
         require => $requiregroups,
-        notify  => $operatingsystem ? {
+        notify  => $::operatingsystem ? {
             OpenBSD => [ Exec["user-mod-${name}"],
                          Exec["user-home-${name}"], ],
             default => undef,