JMS Resource Adapter throws NPE for missing configuration

The JMS resource adapter does not check whether the connection factory jndi bindings have been
configured which leads to a NullPointerException when they are missing, e.g.

WARN [JBossManagedConnectionPool] Throwable while attempting to get a new connection: null
java.lang.NullPointerException
at javax.naming.InitialContext.getURLScheme(InitialContext.java:228)
at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:277)
at javax.naming.InitialContext.lookup(InitialContext.java:351)
at org.jboss.resource.adapter.jms.JmsManagedConnection.setup(JmsManagedConnection.java:712)
<snip/>
ERROR [JmsSessionFactoryImpl] could not create session

We need to throw a more meaningful error message.