quartz: Explicitly compare to HRESULT values.

dlls/quartz/enumfilters.c

@@ -185,7 +185,7 @@ static HRESULT WINAPI IEnumFiltersImpl_Reset(IEnumFilters * iface)
 
     This->uIndex = 0;
     hr = IGraphVersion_QueryVersion(This->pVersionSource, &currentVersion);
-    if (!hr)
+    if (hr == S_OK)
         This->Version = currentVersion;
     return S_OK;
 }

dlls/quartz/filtergraph.c

@@ -1618,7 +1618,7 @@ static HRESULT GetFileSourceFilter(LPCOLESTR pszFileName, IBaseFilter **filter)
     /* Try to find a match without reading the file first */
     hr = GetClassMediaFile(NULL, pszFileName, NULL, NULL, &clsid);
 
-    if (!hr)
+    if (hr == S_OK)
         return CreateFilterInstanceAndLoadFile(&clsid, pszFileName, filter);
 
     /* Now create a AyncReader instance, to check for signature bytes in the file */
@@ -1660,7 +1660,7 @@ static HRESULT GetFileSourceFilter(LPCOLESTR pszFileName, IBaseFilter **filter)
     hr = GetClassMediaFile(pReader, pszFileName, NULL, NULL, &clsid);
     IAsyncReader_Release(pReader);
 
-    if (!hr)
+    if (hr == S_OK)
     {
         /* Release the AsyncReader filter and create the matching one */
         IBaseFilter_Release(*filter);