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
entryElement.setAttribute(ENTRY_ATTVALUE_VALUE, (String) entry.getValue());
					referenceAttributeElement.appendChild(entryElement);
				}
			} else {
				referenceAttributeElement.setAttribute(featureName, String.valueOf(object
						.eGet(feature)));
			}
		} else {
			referenceAttributeElement.setAttribute(UNSET_ATTNAME, UNSET_ATTVALUE_TRUE);
		}
		return referenceAttributeElement;
	}
	private static boolean isStringToStringMap(String featureName) {
		return featureName.equals(CONTRIBUTION_PERSISTEDSTATE_ATTNAME)
				|| featureName.equals(CONTEXT_PROPERTIES_ATTNAME);
	}
	/**
	 * Determines whether this feature is a direct reference to a particular object. That is, the
	 * reference is a 1-1 relationship and the referenced object is not referred by other objects
	 * and is a hard containment feature.
	 * <p>
	 * An example of a direct reference would be a window's main menu. The menu is "owned" by the
	 * window and cannot be one of the menus in a part.
	 * </p>
	 * 
	 * @param featureName
	 *            the name of the interested feature
	 * @return <code>true</code> if this particular feature directly references and "owns" the
	 *         target object, <code>false</code> otherwise
	 * @see #isIndirectReference(String)