dshow: release filter reference obtained from enumeration

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavdevice/dshow.c

@@ -121,10 +121,12 @@ dshow_read_close(AVFormatContext *s)
         if (r == S_OK) {
             IBaseFilter *f;
             IEnumFilters_Reset(fenum);
-            while (IEnumFilters_Next(fenum, 1, &f, NULL) == S_OK)
+            while (IEnumFilters_Next(fenum, 1, &f, NULL) == S_OK) {
                 if (IGraphBuilder_RemoveFilter(ctx->graph, f) == S_OK)
                     IEnumFilters_Reset(fenum); /* When a filter is removed,
                                                 * the list must be reset. */
+                IBaseFilter_Release(f);
+            }
             IEnumFilters_Release(fenum);
         }
         IGraphBuilder_Release(ctx->graph);