Bugfix: Stop command invocation without service

src/Commands/StopCommand.php

@@ -31,7 +31,7 @@ class StopCommand extends Command
         $instanceName = $input->getOption("instance");
         $stopAll = $input->getOption("all");
 
-        if (!($instanceName || $stopAll)) {
+        if (!($serviceName || $stopAll)) {
             $output->writeln("<error>You need to specify a service, or --all</>");
             return self::FAILURE;
         }