Colgate Warns, Shares Hit 4-Year Low  By Brad Dorfman  CHICAGO (Reuters) - Colgate-Palmolive Co. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CL.N target=/stocks/quickinfo/fullquote"&gt;CL.N&lt;/A&gt; on Monday  issued its first formal profit warning in almost a decade,  saying earnings will fall well short of Wall Street forecasts  due to higher marketing spending, sending its shares down 11  percent to a four-year low.