title: add custom Authentication provider on default providerManager
body: <p>i'm starter of spring and security.</p>
  <p>i'm implements custom Authentication provider.</p>
  <p>and add it to the authenticationManager using WebSecurityConfigurerAdapter.</p>
  <p>and i expected ProviderManager's provider's list is defaultAuthenticationProvider( include DaoAuthenticationManager, AnonymousAuthenticaitonManager) and my customProvider.</p>
  <p>But the result was not what I expected.</p>
  <p>The result was two ProviderManagers, separated.</p>
  <p>and if i call AuthenticationManagerBean() then i'll get default provider manager.</p>
  <p>call AuthentcationManager() provider lists include my custom provider.
  Do you use it separately when you actually use it? Or do you integrate providers and use them?</p>
  <p>If so, is there no problem?</p>
  <p>here's my code</p>
  <pre><code>    @Override
      protected void configure(AuthenticationManagerBuilder auth) throws Exception {
          auth.authenticationProvider(jwtAuthenticationProvider);
  
      }
  
      @Override
      protected AuthenticationManager authenticationManager() throws Exception {
          return super.authenticationManager();
      }
  
  
      @Override
      public AuthenticationManager authenticationManagerBean() throws Exception {
          return super.authenticationManagerBean();
      }
  </code></pre>