Krispy Kreme Drops Before Bell  NEW YORK (Reuters) - Shares of Krispy Kreme Doughnuts Inc.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=KKD.N target=/stocks/quickinfo/fullquote"&gt;KKD.N&lt;/A&gt; fell more than 17 percent before the bell on Thursday  after the doughnut chain posted sharply lower quarterly  earnings and signaled that the second half of the year would be  weak.