Detect when standalone-xts.xml falls out of sync

We've been having a problem with updates being made to standalone-full.xml and not being applied to standalone-xts.xml. Most of the time this causes no obvious problem to us, but clearly will cause a problem for our users. If they try to use XTS in conjunction with some other technology, such as JMS, that requires a change to the server config, they will hit problems. However, other times this problem is more obvious as it can prevent the AS from booting or produce errors.

In the long term, we aim to have a better solution to this multiple server config issue. In the short term we need to detect when these files fall out of sync and then create a pull request to fix it.

On failure of the job, we can then fix it manually by:

1. Overwriting standalone-xts.xml with standalone-full.xml.
2. Adding the '<extension module="org.jboss.as.xts"/>' line back in
3. Adding the '<subsystem xmlns="urn:jboss:domain:xts:1.0">' block back in.
4. Jira the problem in the AS7 jira project and name the issue "standalone-xts.xml fallen out of sync with standalone-full.xml" (Essential for demonstrating to the AS7 team that this is a problem)
5. Create a pull request to resolve the issue.

We need an automated way of detecting this problem, so that it can be fixed ASAP.