[Edgent-387] fix usage msg for useGW
diff --git a/connectors/src/main/java/org/apache/edgent/samples/connectors/iotp/IotpAppClient.java b/connectors/src/main/java/org/apache/edgent/samples/connectors/iotp/IotpAppClient.java
index 15508dd..4f4e2dc 100644
--- a/connectors/src/main/java/org/apache/edgent/samples/connectors/iotp/IotpAppClient.java
+++ b/connectors/src/main/java/org/apache/edgent/samples/connectors/iotp/IotpAppClient.java
@@ -35,7 +35,7 @@
  * and subscribes to device events for
  * {@link IotpDeviceSample} and {@link IotpGWDeviceSample}.
  * <p>
- * Usage: {@code [useGw] <app-cfg-path> # see scripts/connectors/iotp/iotp-app-client.cfg}
+ * Usage: {@code [useGW] <app-cfg-path> # see scripts/connectors/iotp/iotp-app-client.cfg}
  * <p>
  * This connects to your IBM Watson IoT Platform service
  * as the Application defined in a application config file.
@@ -48,7 +48,7 @@
  */
 public class IotpAppClient {
   
-  private static final String usage = "[useGw] <app-cfg-path> # see scripts/connectors/iotp/iotp-app-client.cfg";
+  private static final String usage = "[useGW] <app-cfg-path> # see scripts/connectors/iotp/iotp-app-client.cfg";
   
   public static void main(String[] args) throws Exception {
     if (args.length == 0)