Fixes Facts string comparisons in CentOS 7

- CentOS Project has adopted a new rule for versioning numbers. The major number
  matches the RHEL major number, but the minor number is generated from the
  release date. For example, CentOS 7.1407.
- Adds support for Scientific Linux.

Change-Id: I183dd8e0a019d5fb486e8f0641f6ab81ae758f8f
Closes-Bug: 1338777
Signed-off-by: Gael Chamoulaud <gchamoul@redhat.com>
(cherry picked from commit c18884b)

manifests/params.pp

@@ -40,10 +40,17 @@
     $ceph_init_override = '/etc/sysconfig/openstack-cinder-volume'
     $lio_package_name   = 'targetcli'
 
-    if $::operatingsystem == 'RedHat' and $::operatingsystemrelease >= 7 {
-      $iscsi_helper = 'lioadm'
-    } else {
-      $iscsi_helper = 'tgtadm'
+    case $::operatingsystem {
+      'RedHat', 'CentOS', 'Scientific': {
+        if $::operatingsystemmajrelease >= 7 {
+          $iscsi_helper = 'lioadm'
+        } else {
+          $iscsi_helper = 'tgtadm'
+        }
+      }
+      default: {
+        $Iscsi_helper = 'tgtadm'
+      }
     }
 
   } else {