Bug 121498 When datasource/dataset deleted, the datasource/dataset property binding element haven't been deleted
When deleted the datasource/dataset, the datasource/dataset property binding element haven't been deleted. Expected result: This operation must be a transaction.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
* @param namespaceToCheck
	 *            the namespace to check
	 * @return true if the namespace to check is duplicate.
	 */
	public boolean isDuplicateNamespace( String namespaceToCheck )
	{
		Module rootHost = this;
		while ( rootHost instanceof Library
				&& ( (Library) rootHost ).getHost( ) != null )
			rootHost = ( (Library) rootHost ).getHost( );
		List libraries = rootHost.getAllLibraries( );
		Iterator iter = libraries.iterator( );
		while ( iter.hasNext( ) )
		{
			Library library = (Library) iter.next( );
			if ( library.getNamespace( ).equals( namespaceToCheck ) )
				return true;
		}
		return false;
	}
	/**
	 * Finds the property binding defined in this module, which has the same
	 * property name with the given property name and has the same element id of
	 * the given element.
	 * 
	 * @param element
	 *            the element to find
	 * @param propName
	 *            the property name to find
	 * @return the matched property binding defined in the module, otherwise