quartz: Reject samples in video renderer when stopped.

When stopped video renderer no longer updates, so don't even try.
diff --git a/dlls/quartz/videorenderer.c b/dlls/quartz/videorenderer.c
index f0a73d7..4c06c44 100644
--- a/dlls/quartz/videorenderer.c
+++ b/dlls/quartz/videorenderer.c
@@ -357,8 +357,11 @@
     REFERENCE_TIME tStart, tStop;
     HRESULT hr;
 
+    if (This->state == State_Stopped)
+        return S_FALSE;
+
     TRACE("%p %p\n", iface, pSample);
-    
+
     hr = IMediaSample_GetPointer(pSample, &pbSrcStream);
     if (FAILED(hr))
     {