Empty <dd> tags mis-aligns <dd> that follow

Created by: eleven41

When an empty or self-closing <dd> tag is used in a horizontal <dl>, the <dd> tags following it are mis-aligned with the matching <dt> tags.

 <dl class="dl-horizontal">
   <dt>Title 1</dt>
   <dd>Description 1</dd>

   <dt>Title 2</dt>
   <dd></dd>

   <dt>Title 3</dt>
   <dd>Description 3</dd>
</dl>

Here is a jsFiddle: http://jsfiddle.net/xjQX3/

In the above example, "Description 3" will sit beside "Title 2". It should sit beside "Title 3". If the <dl> is not horizontal, then they appear as expected.