Depois que fiz esse exercício minha aplicação deixou de se logar, apresentando mensagem de usuario nçao encontrado | Java e JSF 2 - III: Integração com CDI

package br.com.caelum.livraria.dao;

import java.io.Serializable;

import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.persistence.NoResultException;
import javax.persistence.TypedQuery;

import br.com.caelum.livraria.modelo.Usuario;

@SuppressWarnings("serial")
public class UsuarioDao implements Serializable {

    @Inject
    EntityManager manager;

    public boolean existe(Usuario usuario) {

        System.out.println("usuario:" + usuario.getEmail());
        System.out.println("senha:" + usuario.getSenha());
         TypedQuery<Usuario> query = manager.createQuery("select u from Usuario u where u.email = :pEmail and u.senha = :pSenha",Usuario.class);

         query.setParameter("pEmail", usuario.getEmail());
         query.setParameter("pSenha", usuario.getSenha());

         try {
             Usuario resultado =  query.getSingleResult();
         } catch (NoResultException ex){
             return false;
         }

         return true;
    }
}

package br.com.caelum.livraria.bean;

import java.io.Serializable;

import javax.faces.application.FacesMessage;
import javax.faces.bean.ViewScoped;
import javax.faces.context.FacesContext;
import javax.inject.Inject;
import javax.inject.Named;

import br.com.caelum.livraria.dao.UsuarioDao;
import br.com.caelum.livraria.modelo.Usuario;

@Named
@ViewScoped
@SuppressWarnings("serial")
public class LoginBean implements Serializable {

    @Inject
    UsuarioDao usuarioDao;

    @Inject
    FacesContext context;

    private Usuario usuario = new Usuario();

    public Usuario getUsuario() {
        return usuario;
    }

    public String efetuarLogin() {
        System.out.println("Efetuando login do usuario" + this.usuario.getEmail());

        boolean existe = usuarioDao.existe(this.usuario);

        if (existe) {
            context.getExternalContext().getSessionMap().put("usuarioLogado", this.usuario);
            return "livro?faces-redirect=true";
        }

        context.addMessage(null, new FacesMessage("Usuario nao encontrado"));
        return "login";
    }

    public String deslogar() {
        context.getExternalContext().getSessionMap().remove("usuarioLogado");
        return "login?faces-redirect=true";

    }
}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:h="http://xmlns.jcp.org/jsf/html"
    xmlns:f="http://xmlns.jcp.org/jsf/core"
    xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
    xmlns:p="http://primefaces.org/ui">

<ui:composition template="_template.xhtml">
    <ui:define name="titulo">
        <p:outputPanel>Login</p:outputPanel>
    </ui:define>
    <ui:define name="conteudo">
        <p:messages globalOnly="true"/>
        <h:form id="login">
            <p:fieldset legend="Login">
                <h:panelGrid columns="3">
                    <p:outputLabel value="Email:" for="email" />
                    <p:inputText id="email" value="#{loginBean.usuario.email}" required="true">
                        <f:passThroughAttribute name="type" value="email" />
                     </p:inputText>
                     <p:message for="email" id="messageEmail" />

                    <p:outputLabel value="Senha:" for="senha" />
                    <p:password id="senha" value="#{loginBean.usuario.senha}" feedback="true" required="true" />
                    <p:message for="senha" id="messageSenha" />
                    <p:commandButton value="Efetue login" action="#{loginBean.efetuarLogin}" update="@form" process="@form" />
                </h:panelGrid>
            </p:fieldset>
        </h:form>

    </ui:define>
</ui:composition>

</html>

PARTE DO LOG:

INFO: Starting ProtocolHandler ["ajp-nio-8009"] Aug 02, 2016 10:38:35 AM org.apache.catalina.startup.Catalina start INFO: Server startup in 15568 ms FASE: RESTORE_VIEW 1 FASE: RESTORE_VIEW 1 /login.xhtml FASE: RENDER_RESPONSE 6 /login.xhtml FASE: APPLY_REQUEST_VALUES 2 FASE: PROCESS_VALIDATIONS 3 FASE: UPDATE_MODEL_VALUES 4 FASE: INVOKE_APPLICATION 5 Efetuando login do usuarionull usuario:null senha:null Aug 02, 2016 10:38:39 AM org.hibernate.annotations.common.Version INFO: HCANN000001: Hibernate Commons Annotations {4.0.1.Final} Aug 02, 2016 10:38:39 AM org.hibernate.Version logVersion INFO: HHH000412: Hibernate Core {4.1.8.Final} Aug 02, 2016 10:38:39 AM org.hibernate.cfg.Environment

Projeto no bitbucket https://bitbucket.org/arogeriop/livraria.git