indeo3: when freeing buffers, set pointers referencing them to NULL as well

libavcodec/indeo3.c

@@ -209,6 +209,7 @@ static av_cold void free_frame_buffers(Indeo3DecodeContext *ctx)
     for (p = 0; p < 3; p++) {
         av_freep(&ctx->planes[p].buffers[0]);
         av_freep(&ctx->planes[p].buffers[1]);
+        ctx->planes[p].pixels[0] = ctx->planes[p].pixels[1] = 0;
     }
 }