fix: set default for use_networkd (#247)

- resolving issue where the systemd::manage_networkd is missing for most
  hosts, setting a default

Reviewed-on: https://git.query.consul/unkinben/puppet-prod/pulls/247

modules/networking/manifests/init.pp

@@ -4,7 +4,7 @@ class networking (
   Hash $interface_defaults = {},
   Hash $routes = {},
   Hash $route_defaults = {},
-  Boolean $use_networkd = lookup('systemd::manage_networkd'),
+  Boolean $use_networkd = lookup('systemd::manage_networkd', undef, undef, false),
 ){
 
   include network