Fix a typo.

[SVN r28496]

status/explicit-failures-markup.xml

@@ -1764,7 +1764,7 @@ for more information.
                 <toolset name="vc-8_0"/>
                 <toolset name="sunpro-5_3"/>
                 <toolset name="tru64cxx65-042"/>
-                <note author="John Maddock"/ refid="2">
+                <note author="John Maddock" refid="2"/>
             </mark-failure>
         </test>
         <mark-expected-failures>