No timeout limit as sample uses while true (GoogleCloudPlatform#1238)

* Unfounded timeout limit as sample uses while true

* Update README.md

pubsub/cloud-client/README.md

@@ -47,7 +47,7 @@ Publishes 5 messages to the topic `my-topic`.
 ```
    mvn exec:java -Dexec.mainClass=com.example.pubsub.SubscriberExample -Dexec.args=my-sub
 ```
-Subscriber will continue to listen on the topic for 5 minutes and print out message id and data as messages are received.
+Subscriber will continue to listen on the topic and print out message id and data as messages are received. Press `Ctrl+C` to exit the application. 
 
 #### Testing
 Run the test with Maven.