Not possible change the object store type from hornetq to jdbc via cli commands

When you have set the object store to be type of hornetq and then you change your mind to set it for jdbc object store the jboss-cli permits this operation but no change is propagated to model and XML file.

How to reproduce:

1. ./bin/standalone.xml (start eap 6.2.0.GA)
2. ./bin/jboss-cli.sh -c (connect to running eap)
3. /subsystem=transactions:write-attribute(name=use-hornetq-store, value=true)
4. :reload
5. /subsystem=transactions/log-store=log-store:read-attribute(name=type)
6. /subsystem=transactions:write-attribute(name=use-jdbc-store, value=true)
7. :reload
8. /subsystem=transactions/log-store=log-store:read-attribute(name=type)

The object store stays to be set to hornetq and no change happens in the standalone.xml file.