KieBase including resources from other KieBase fails to compile when it declares a fact

Description of problem:

When a KieBase is defined in kmodule.xml in a way that it includes resources from other KieBase, and the included resources contain a DRL defining a fact, the KieBuilder fails with the following message:

2013-06-20 18:41:39,605 [main] ERROR Unable to build KieBaseModel:defaultKBase
New declaration of org.drools.compiler.integrationtests.CancelFact can't declare new fields

The declaration of CancelFact is located in one DRL file only. The same DRL file is used by both defined KieBases. Please see the attached pull request with reproducer for details.

Version-Release number of selected component (if applicable):

Drools 6.0.0-SNAPSHOT
very likely Drools 6.0.0.Beta4 (not released yet)

This worked fine with Drools 6.0.0.Beta3, so it seems to be a regression.

How reproducible:

Run the test case in attached pull request.

Actual results:

The KieBase does not compile.

Expected results:

The KieBase compiles, test succeeds.