Code simplifications found by cppcheck

They are based on:
- Boolean arithmetic simplifications
- setting variables that are not accessed
- constant variables

modules/vorbis/audio_stream_ogg_vorbis.cpp

@@ -438,9 +438,7 @@ void AudioStreamOggVorbis::maybe_update_info() {
 		}
 		if (i == 0) {
 			packet->b_o_s = 1;
-		}
 
-		if (i == 0) {
 			ERR_FAIL_COND(!vorbis_synthesis_idheader(packet));
 		}