Support deployment on Jboss 4.x

Caused by: javax.naming.NamingException: resource-ref: jdbc/XWikiDS has no valid JNDI binding. Check the jboss-web/resource-ref.
at org.jboss.web.AbstractWebDeployer.linkResourceRefs(AbstractWebDeployer.java:610)
at org.jboss.web.AbstractWebDeployer.parseWebAppDescriptors(AbstractWebDeployer.java:508)
at org.jboss.web.AbstractWebDeployer$DescriptorParser.parseWebAppDescriptors(AbstractWebDeployer.java:865)
at org.jboss.web.tomcat.tc5.TomcatDeployer.performDeployInternal(TomcatDeployer.java:157)
at org.jboss.web.tomcat.tc5.TomcatDeployer.performDeploy(TomcatDeployer.java:103)
at org.jboss.web.AbstractWebDeployer.start(AbstractWebDeployer.java:371)
... 67 more
19:17:44,836 ERROR [MainDeployer] Could not start deployment: file:/opt/jboss-4.0.5.GA/server/default/deploy/xwiki-1.0-beta-5.war/
org.jboss.deployment.DeploymentException: Error during deploy; - nested throwable: (javax.naming.NamingException: resource-ref: jdbc/XWikiDS has no valid JNDI binding. Chec
k the jboss-web/resource-ref.)
at org.jboss.web.AbstractWebDeployer.start(AbstractWebDeployer.java:380)
at org.jboss.web.WebModule.startModule(WebModule.java:83)
at org.jboss.web.WebModule.startService(WebModule.java:61)
at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289)