Bug 317954 Version deltas file so that incompatible changes will be ignored
The deltas file needs to be versioned so that incompatible changes will be discarded allowing the workbench to be constructed as if there were no deltas in existence.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/XMLModelReconciler.java
for (int i = 0; i < nodeList.getLength(); i++) {
			Node node = nodeList.item(i);
			if (!(node instanceof Element)) {
				continue;
			}
			Element innerElement = (Element) node;
			String featureName = innerElement.getNodeName();
			EStructuralFeature feature = getStructuralFeature(object, featureName);
			if (feature != null) {
				if (isChainedReference(featureName)) {
					ModelDelta delta = createMultiReferenceDelta(deltas, references, object,
							feature, innerElement);
					deltas.add(delta);
				} else if (isUnset(innerElement)) {
					ModelDelta delta = new EMFModelDeltaUnset(object, feature);
					deltas.add(delta);
				} else if (isDirectReference(featureName)) {
					ModelDelta delta = createDirectReferenceDelta(deltas, references, object,
							feature, innerElement);
					deltas.add(delta);
				} else if (isIndirectReference(featureName)) {
					ModelDelta delta = createIndirectReferenceDelta(references, object, feature,
							innerElement);
					deltas.add(delta);
				} else if (isUnorderedChainedAttribute(featureName)) {
					ModelDelta delta = createUnorderedChainedAttributeDelta(object, feature,
							innerElement, featureName);
					deltas.add(delta);
				} else if (isStringToStringMap(featureName)) {
					ModelDelta delta = createMapDelta(object, innerElement, feature);