Found it. pool-name attribute is required. I wish the documentation was better written. I shouldn't have to comb through the schema to find out how to configure this product. Especially since it wasn't required in the previous version of Jboss that we were using.
<datasource jndi-name="java:/ourapp/LoginDataSource" pool-name="login-datasource" enabled="true" use-java-context="false">
I'd request that you fix the error message in future releases to make them match the more informative errors thrown when other configuration parsing errors occur. Like this one:
Message: JBAS014724: Missing required attribute(s): class-name