fix: compat with newer stdlib

Author: costowell

manifests/init.pp

@@ -131,7 +131,7 @@
 
       $opt_password = ['--password', $password]
 
-      if is_array($server) {
+      if $server =~ Array {
         # Transform ['a','b'] -> ['--server','a','--server','b']
         $opt_server = split(join(prefix($server, '--server|'), '|'), '\|')
       } elsif !empty($server) {