hlsdemux2: Fix buffer leak when resynching

Unref the buffer in gst_hls_demux_handle_buffer() when
returning GST_ADAPTIVE_DEMUX_FLOW_LOST_SYNC

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2849>

subprojects/gst-plugins-good/ext/adaptivedemux2/hls/gsthlsdemux.c

@@ -1484,6 +1484,8 @@ gst_hls_demux_handle_buffer (GstAdaptiveDemux * demux,
    */
   if (hls_stream->current_segment == NULL) {
     GST_WARNING_OBJECT (stream, "Lost sync");
+    /* Drop the buffer */
+    gst_buffer_unref (buffer);
     return GST_ADAPTIVE_DEMUX_FLOW_LOST_SYNC;
   }