Fix syntax for puppet 4 support

On older versions of puppet (discovered on 4.10.7)
this select statement fails and $_local_user_home
ends up with the boolean value 'false' instead of
one of the strings you would expect.

Author: quentins

manifests/registry.pp

@@ -68,7 +68,7 @@
       $_local_user_home = $local_user_home
     } else {
       # set sensible default
-      $_local_user_home = $local_user == 'root' ? {
+      $_local_user_home = ($local_user == 'root') ? {
         true    => '/root',
         default => "/home/${local_user}",
       }