[enterBr] undesired paragraph in blockquote

[Garry Yao]

1. With enterMode = CKEDITOR.ENTER_BR open any sample page;
2. Clear page content and click on "blockquote";
   • Actual Result:

     <blockquote>
     	<p>
     		&nbsp;</p>
     </blockquote>
     

   • Expected Result: There's no created paragraph.

[Wiktor Walc]

Same with div coniatner.

[Krzysztof Studnik]

I think TT made for #6566 r6493 reveals strange behaviour of setting blockquote on selection in entermode = BR.
selected 2 lines

[2<br />
3]<br />

are first converted into

<p>2<br /> 
3</p>

and then to

<blockquote>
  <p>2<br /> 
  3</p>
</blockquote>

I hope it could be useful for investigation.