Bug 139986 [CommonNavigator] Convert catch(Error/Throwable) to SafeRunner
In several places the CN framework uses catch(Error/Throwable) to ensure that code does not bring the framework down. Change these to use SafeRunner.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/NavigatorContentDescriptor.java
} else if (children.length > 1) {
			throw new WorkbenchException(NLS.bind(
					CommonNavigatorMessages.Attribute_Missing_Warning,
					new Object[] {
							TAG_ENABLEMENT,
							id,
							configElement.getDeclaringExtension()
									.getNamespaceIdentifier() }));
		}
		children = configElement.getChildren(TAG_OVERRIDE);
		if (children.length == 0) {
			overridePolicy = OverridePolicy.get(OverridePolicy.InvokeAlwaysRegardlessOfSuppressedExt_LITERAL);
		} else if (children.length == 1) {
			suppressedExtensionId = children[0]
					.getAttribute(ATT_SUPPRESSED_EXT_ID);
			overridePolicy = OverridePolicy.get(children[0]
					.getAttribute(ATT_POLICY));
		} else if (children.length > 1) {
			throw new WorkbenchException(NLS.bind(
					CommonNavigatorMessages.Too_many_elements_Warning,
					new Object[] {
							TAG_OVERRIDE,
							id,configElement.getDeclaringExtension()
							.getNamespaceIdentifier() }));
		}
	}
	/**
	 * @return Returns the icon.
	 */
	public String getIcon() {