handle Ubuntu better

manifests/debian.pp

@@ -51,8 +51,14 @@ class su_apache::debian (
 
   $debian_major_version = $facts['os']['distro']['release']['major']
 
-  if (Integer($debian_major_version) < 9) {
-    fail("This class only works with Debian stretch and later")
+  if ($facts['os']['name'] == 'Debian') {
+    if (Integer($debian_major_version) < 9) {
+      fail("This class only works with Debian stretch and later")
+    }
+  } elsif ($facts['os']['name'] == 'Ubuntu') {
+    if (Float($debian_major_version) < 16.0) {
+      fail("This class only works with Ubuntu xenial and later")
+    }
   }
 
   # Set the SSL/TLS protocols and ciphers.