Revert "Update HenshinResource to use XMI IDs by default"

This reverts commit de0d9dea7c3efeb991e86a71439a87ef8f12ceee.

Change-Id: Ia6f25deb4f5979b80ca800170d33e43344fcd4ef
Reason: After this commit, the build failed due to a problem with the unit tests for the Giraph code generation component. I revert the commit to see if it is indeed the reason for the failing build.
diff --git a/plugins/org.eclipse.emf.henshin.model/src/org/eclipse/emf/henshin/model/resource/HenshinResource.java b/plugins/org.eclipse.emf.henshin.model/src/org/eclipse/emf/henshin/model/resource/HenshinResource.java
index 7929bcd..02a49dc 100644
--- a/plugins/org.eclipse.emf.henshin.model/src/org/eclipse/emf/henshin/model/resource/HenshinResource.java
+++ b/plugins/org.eclipse.emf.henshin.model/src/org/eclipse/emf/henshin/model/resource/HenshinResource.java
@@ -40,11 +40,6 @@
 		setIntrinsicIDToEObjectMap(new HashMap<String, EObject>());
 	}
 	
-	@Override
-	protected boolean useIDs() {
-		return true;
-	}
-	
 	/**
 	 * Constructor.
 	 * @param uri URI of a Henshin resource.