Description of problem:

I have generated the response xml file for installing jboss eap 6 (auto.xml),which also created the auto.xml.variable file.  I have another JBoss instance running on system, so I have modified management ports in auto.xml.variables

~~~
domain.management-http = 19990
domain.management-native = 19999
~~~
When we try to install JBoss instance using following command it fails with exception:

$ java -jar /path/to/jboss-as-server-installer-6.4.0.jar /path/to/auto.xml

~~~
The port 9999 is already in use, and may be required to be open for this installation. Do you wish to continue?
~~~

Version-Release number of selected component (if applicable):
JBoss EAP 6.x

How reproducible:


Steps to Reproduce:
1. 
2.
3.

Actual results:
After modifying auto.xml file, we should be able install JBoss server instance.

Expected results:
Not able to install JBoss server after modification in auto.xml


Additional info:
The installer seems to have a class that validates port, uses hardcoded port:
NoPortClashValidator.class:
~~~~
if (!available(9999))
    {
      this.warning = "NoPortClashValidator.warning";
      setMessage(idata.langpack.getString(this.warning));
      return DataValidator.Status.WARNING;
  }
~~~~