flacenc: Pass audio info from set_format() to query_total_samples() explicitly

This fixes writing of the seek table header.

gst_audio_encoder_get_audio_info() will still return old/unset audio
info until set_format() has actually returned, which then results in
query_total_samples() to always return 0.

Thanks to Jacob Kauffmann for debugging this and finding the main cause.

Fixes #756

Part-of: <!661>

ext/flac/gstflacenc.c

@@ -811,11 +811,10 @@ gst_flac_enc_getcaps (GstAudioEncoder * enc, GstCaps * filter)
 }
 
 static guint64
-gst_flac_enc_peer_query_total_samples (GstFlacEnc * flacenc, GstPad * pad)
+gst_flac_enc_peer_query_total_samples (GstFlacEnc * flacenc, GstPad * pad,
+    GstAudioInfo * info)
 {
   gint64 duration;
-  GstAudioInfo *info =
-      gst_audio_encoder_get_audio_info (GST_AUDIO_ENCODER (flacenc));
 
   GST_DEBUG_OBJECT (flacenc, "querying peer for DEFAULT format duration");
   if (gst_pad_peer_query_duration (pad, GST_FORMAT_DEFAULT, &duration)
@@ -884,7 +883,7 @@ gst_flac_enc_set_format (GstAudioEncoder * enc, GstAudioInfo * info)
       flacenc->channel_reorder_map);
 
   total_samples = gst_flac_enc_peer_query_total_samples (flacenc,
-      GST_AUDIO_ENCODER_SINK_PAD (enc));
+      GST_AUDIO_ENCODER_SINK_PAD (enc), info);
 
   FLAC__stream_encoder_set_bits_per_sample (flacenc->encoder,
       GST_AUDIO_INFO_DEPTH (info));