KnowledgeAgent cannot handle packages from Guvnor

When applying a changeset on a KnowledgeBase, which sources a package from Guvnor, I get a client exception. I believe this is because Guvnor 5.1 now requires a HTTP authentication to fetch the package and the KnowledgeAgent code cannot handle that in any way. This is the exception I get:

java.lang.RuntimeException: KnowledgeAgent exception while trying to deserialize KnowledgeDefinitionsPackage
...
Caused by: java.io.IOException: Server returned HTTP response code: 401 for URL: http://localhost:8080/jboss-brms/org.drools.guvnor.Guvnor/package/mortgages1/LATEST

And this is the changeset that I am supplying:
<change-set xmlns='http://drools.org/drools-5.1/change-set' xmlns:xs='http://www.w3.org/2001/XMLSchema-instance' xs:schemaLocation='http://drools.org/drools-5.1/change-set drools-change-set-5.1.xsd'>
<add><resource source='http://localhost:8080/jboss-brms/org.drools.guvnor.Guvnor/package/mortgages1/LATEST' type='PKG' /></add>
</change-set>

It doesn't work even when I use http://admin:admin@localhost:8080/ instead of a simple http://localhost:8080/.

This is a regression - Guvnor 5.0 didn't require HTTP auth to do this and thus this particular use case functioned properly.