Sabre Buys Reservation Services Company  NEW YORK (Reuters) - Sabre Holdings Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=TSG.N target=/stocks/quickinfo/fullquote"&gt;TSG.N&lt;/A&gt;, owner of  the Travelocity Web site, on Thursday said it agreed to buy  privately held SynXis Corp., a provider of reservation  management services to hotels, for \$40 million.