correct output description - only one task is running on manager

Signed-off-by: Charles Smith <charles.smith@docker.com>
(cherry picked from commit 5f219806fce6c70bfea1a610476e7e3e6e78371d)

docs/swarm/swarm-tutorial/scale-service.md

@@ -51,7 +51,7 @@ service running in the swarm:
 
     You can see that swarm has created 4 new tasks to scale to a total of 5
     running instances of Alpine Linux. The tasks are distributed between the
-    three nodes of the swarm. Two are running on `manager1`.
+    three nodes of the swarm. One is running on `manager1`.
 
 4. Run `docker ps` to see the containers running on the node where you're
 connected. The following example shows the tasks running on `manager1`: