Prevent StackOverFlowError in AxisServlet

There is a potential for a StackOverFlowError in the AxisServlet's init() methods. Since the init() potentially calls init(ServletConfig), depending on the underlying Servlet implementation utilized, this could cause issues. A simple flag can be set in the init(ServletConfig) method to indicate it has already been called on a specific AxisServlet instance. If it has been called, the init() method should not need to call it yet again.