more graph library markup

[SVN r25246]

status/explicit-failures-markup.xml

@@ -324,6 +324,12 @@
             <toolset name="vc7"/>
             <note refid="3" author="D. Gregor"/>
         </mark-expected-failures>
+        <mark-expected-failures>
+            <test name="betweenness_centrality_test"/>
+            <toolset name="intel-win32-7.1-vc6*"/>
+            <toolset name="vc7"/>
+            <note refid="3" author="Aleksey Gurtovoy"/>
+        </mark-expected-failures>
     </library>