yum: Added description and os check to yum::repo::elrepo.

yum/manifests/init.pp

@@ -344,10 +344,16 @@ class yum::repo::dell {
 }
 
 
+# Add ELRepo repository
+#
 class yum::repo::elrepo {
 
     include yum::common
 
+    if $yum::common::osname != "el" {
+        fail("ELRepo repository not supported in ${::operatingsystem}")
+    }
+
     yum::repo { "elrepo":
         descr      => "ELRepo.org Community Enterprise Linux Repository",
         mirrorlist => "http://elrepo.org/mirrors-elrepo.el${yum::common::osver}",