demos/policy-transaction - add instruction for fuse

mvn exec:java -Dexec.args="activemq"

[INFO] --- exec-maven-plugin:1.4.0:java (default-cli) @ switchyard-demo-policy-transaction ---
Using queue name: policyQSTransacted
Using payload: rollback.A
[WARNING] 
java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:293)
	at java.lang.Thread.run(Thread.java:745)
Caused by: javax.jms.JMSException: User name [karaf] or password is invalid.
	at org.apache.activemq.util.JMSExceptionSupport.create(JMSExceptionSupport.java:49)
	at org.apache.activemq.ActiveMQConnection.syncSendPacket(ActiveMQConnection.java:1391)
	at org.apache.activemq.ActiveMQConnection.ensureConnectionInfoSent(ActiveMQConnection.java:1496)
	at org.apache.activemq.ActiveMQConnection.start(ActiveMQConnection.java:524)
	at org.switchyard.quickstarts.demo.policy.transaction.JMSClient.sendToActiveMQ(JMSClient.java:119)
	at org.switchyard.quickstarts.demo.policy.transaction.JMSClient.main(JMSClient.java:82)
	... 6 more