title: @GeneratedValue(strategy=GenerationType.AUTO) does not create id for embedded setup
body: <p>I have the following database setup using Spring and Hibernate as JPA implementor.
  I have a entity class extending org.springframework.data.jpa.domain.AbstractPersistable which basically defines an id attribute with a generation strategy of AUTO.</p>
  
  <p>If read everything correctly, this would mean that the JPA implementor, Hibernate in my case, is responsible for generating the id.</p>
  
  <p>It does work for an actual setup using PostgreSQL but not for this embedded setup:</p>
  
  <pre><code>    &lt;jdbc:embedded-database id="dataSource" type="HSQL"&gt;
          &lt;jdbc:script location="classpath:/sql/schema.sql" /&gt;
      &lt;/jdbc:embedded-database&gt;
  
      &lt;bean
          class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" /&gt;
      &lt;bean id="entityManagerFactory"
          class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"&gt;
          &lt;property name="dataSource" ref="dataSource" /&gt;
          &lt;property name="jpaVendorAdapter"&gt;
              &lt;bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"&gt;
                  &lt;property name="databasePlatform" value="org.hibernate.dialect.HSQLDialect" /&gt;
              &lt;/bean&gt;
          &lt;/property&gt;
      &lt;/bean&gt;
  
      &lt;bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"&gt;
          &lt;property name="entityManagerFactory" ref="entityManagerFactory" /&gt;
      &lt;/bean&gt;
  </code></pre>
  
  <p>Entity class</p>
  
  <pre><code>@Entity
  public class Account extends AbstractPersistable&lt;Long&gt; {
  
      private static final long serialVersionUID = 1L;
  
      @NotNull
      @Size(min=1, max=25)
      private String name;
  }
  </code></pre>