Bug 158065 [DataBinding] ValidationError observables need a nudge to hook themselves up
See attached patch.
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/observable/value/ComputedValue.java
private boolean dirty = true;
	private boolean stale = false;
	private Object cachedValue = null;
	/**
	 * Dependencies list. This is a collection that contains no duplicates. It
	 * is normally an ArrayList to conserve memory, but if it ever grows above a
	 * certain number of elements, a HashSet is substited to conserve runtime.
	 */
	private IObservable[] dependencies = new IObservable[0];
	/**
	 * 
	 */
	public ComputedValue() {