public java.lang.String getViewState(javax.faces.context.FacesContext facesContext,
This method returns the flow execution key to be used as the value for the "javax.faces.ViewState" hidden input
field. The value of this key is not important because JSF state is stored in a Web Flow managed view scoped
variable. However the presence of the view state parameter alone is important for triggering actions. Hence we
return the most logical value, which is the flow execution key.