SUBMARINE-57. Add more elaborate message if submarine command is not recognized. Contributed by Adam Antal

hadoop-submarine/hadoop-submarine-core/src/main/java/org/apache/hadoop/yarn/submarine/client/cli/Cli.java

@@ -100,7 +100,7 @@ public static void main(String[] args) throws Exception {
       }
     } else {
       printHelp();
-      throw new IllegalArgumentException("Bad parameters <TODO>");
+      throw new IllegalArgumentException("Unrecognized option: " + args[0]);
     }
   }
 }