plugins/routing/activemq: s/TOPIC/DESTINATION/

In the ActiveMQ routing plug-in, change the `ACTIVEMQ_TOPIC` setting to be `ACTIVEMQ_DESTINATION` as the value may be either a topic or a queue.

For compatibility, `ACTIVEMQ_TOPIC` is used if` ACTIVEMQ_DESTINATION` is not specified.

This commit fixes bug 1110454.