Ticket: #6687 - Empty tag should be removed on inline-style format

=== TC 1 ===
 1. under IE double-click the boundary of fieldset
 1. switch to Source mode
 * Result should be: {{{
        caption
        keep going, CKeditor!
    }}}
=== TC 2 ===
 1. Under Firefox 3.6 click the legend
 1. switch to Source mode
 * Result should be: {{{
        caption
        keep going, CKeditor!
    }}}

Editor 1