Fixed a misspelled platform name.

[SVN r33448]

status/explicit-failures-markup.xml

@@ -4000,6 +4000,7 @@ for more information.
         <mark-expected-failures>
             <test name="testwave"/>
             <toolset name="qcc-3.3.5_gpp"/>
+            <toolset name="qcc-3.3.5-gpp"/>
             <note author="Hartmut Kaiser" refid="29"/>
         </mark-expected-failures>