mediadecoder: fix crash on hang up

introduced in 207f0d

avformat_close_input() does all the job and nullptr the given pointer.

Tuleap: #412
Change-Id: I3104d5dd66e3207d535dca332f8c9ce2463373a1

src/media/media_decoder.cpp

@@ -48,17 +48,8 @@ MediaDecoder::~MediaDecoder()
 {
     if (decoderCtx_)
         avcodec_close(decoderCtx_);
-
-    if (inputCtx_) {
-        if (inputCtx_->nb_streams > 0) {
-#if LIBAVFORMAT_VERSION_CHECK(53, 17, 0, 25, 0)
+    if (inputCtx_)
         avformat_close_input(&inputCtx_);
-#else
-            av_close_input_file(inputCtx_);
-#endif
-        }
-        avformat_free_context(inputCtx_);
-    }
 
     av_dict_free(&options_);
 }