Boeing Gets \$891 Mln Air Force C-17 Deal  WASHINGTON (Reuters) - Boeing Co. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=BA.N target=/stocks/quickinfo/fullquote"&gt;BA.N&lt;/A&gt; has been awarded  an \$891.6 million U.S. Air Force contract modification for  continued maintenance of the C-17 Globemaster III transport  fleet, the Pentagon said Friday.