CppEditor: Do not return double entries in FunctionHelper::overrides()

Change-Id: I568cdb842fd823067514dd4b2e983e6bd19eebca
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/cppeditor/cppvirtualfunctionassistprovider.cpp

@@ -263,9 +263,6 @@ QList<Symbol *> FunctionHelper::overrides(Class *startClass, Function *function,
     const Name *referenceName = function->name();
     QTC_ASSERT(referenceName && referenceType.isValid(), return result);
 
-    // Add itself
-    result << function;
-
     // Find overrides
     CppEditor::Internal::CppClass cppClass = CppClass(startClass);
     cppClass.lookupDerived(startClass, snapshot);