Remove unnecessary error logs

When a call to a packet or frame sink fails, do not log the error on the
caller side: either the "failure" is expected (explicitly stopped) or it
must be logged by the packet or frame sink implementation.

app/src/decoder.c

@@ -29,7 +29,6 @@ sc_decoder_open_sinks(struct sc_decoder *decoder) {
     for (unsigned i = 0; i < decoder->sink_count; ++i) {
         struct sc_frame_sink *sink = decoder->sinks[i];
         if (!sink->ops->open(sink)) {
-            LOGE("Could not open frame sink %d", i);
             sc_decoder_close_first_sinks(decoder, i);
             return false;
         }
@@ -63,7 +62,6 @@ sc_decoder_open(struct sc_decoder *decoder, const AVCodec *codec) {
     }
 
     if (!sc_decoder_open_sinks(decoder)) {
-        LOGE("Could not open decoder sinks");
         av_frame_free(&decoder->frame);
         avcodec_close(decoder->codec_ctx);
         avcodec_free_context(&decoder->codec_ctx);
@@ -86,7 +84,6 @@ push_frame_to_sinks(struct sc_decoder *decoder, const AVFrame *frame) {
     for (unsigned i = 0; i < decoder->sink_count; ++i) {
         struct sc_frame_sink *sink = decoder->sinks[i];
         if (!sink->ops->push(sink, frame)) {
-            LOGE("Could not send frame to sink %d", i);
             return false;
         }
     }

app/src/demuxer.c

@@ -111,7 +111,6 @@ push_packet_to_sinks(struct sc_demuxer *demuxer, const AVPacket *packet) {
     for (unsigned i = 0; i < demuxer->sink_count; ++i) {
         struct sc_packet_sink *sink = demuxer->sinks[i];
         if (!sink->ops->push(sink, packet)) {
-            LOGE("Could not send packet to sink %d", i);
             return false;
         }
     }
@@ -148,7 +147,6 @@ sc_demuxer_open_sinks(struct sc_demuxer *demuxer, const AVCodec *codec) {
     for (unsigned i = 0; i < demuxer->sink_count; ++i) {
         struct sc_packet_sink *sink = demuxer->sinks[i];
         if (!sink->ops->open(sink, codec)) {
-            LOGE("Could not open packet sink %d", i);
             sc_demuxer_close_first_sinks(demuxer, i);
             return false;
         }
@@ -184,7 +182,6 @@ run_demuxer(void *data) {
     }
 
     if (!sc_demuxer_open_sinks(demuxer, codec)) {
-        LOGE("Could not open demuxer sinks");
         goto end;
     }