Puppet: Fix epel to use the major release version of the OS

refs #9453

.puppet/modules/epel/manifests/init.pp

@@ -15,10 +15,10 @@
 class epel {
 
   yumrepo { 'epel':
-    mirrorlist => "http://mirrors.fedoraproject.org/mirrorlist?repo=epel-6&arch=${::architecture}",
+    mirrorlist => "http://mirrors.fedoraproject.org/mirrorlist?repo=epel-${::operatingsystemmajrelease}&arch=${::architecture}",
     enabled    => '1',
     gpgcheck   => '0',
-    descr      => "Extra Packages for Enterprise Linux 6 - ${::architecture}"
+    descr      => "Extra Packages for Enterprise Linux ${::operatingsystemmajrelease} - ${::architecture}"
   }
 }