Fix for compile error on recent clang.

BUG=webrtc:7235
TBR=tommi@webrtc.org

Review-Url: https://codereview.webrtc.org/2713383003 .
diff --git a/Samples/multimedia/directshow/baseclasses/wxdebug.cpp b/Samples/multimedia/directshow/baseclasses/wxdebug.cpp
index 5763891..6efa736 100644
--- a/Samples/multimedia/directshow/baseclasses/wxdebug.cpp
+++ b/Samples/multimedia/directshow/baseclasses/wxdebug.cpp
@@ -1234,7 +1234,7 @@
     hr = pUnk->QueryInterface(IID_IPin, (void **)&pp);

     if(SUCCEEDED(hr))

     {

-        CDisp::CDisp(static_cast<IPin*>(pp));

+        CDisp dummy(static_cast<IPin*>(pp));

         pp->Release();

         return;

     }