removed unusability of serialization on acc

[SVN r29821]

status/explicit-failures-markup.xml

@@ -1253,7 +1253,6 @@ for more information.
     <!-- serialization -->
     <library name="serialization">
         <mark-unusable>
-            <toolset name="acc*" />
             <toolset name="vacpp*" />
             <toolset name="mipspro*" />
             <toolset name="dmc*" />