vorbisenc: fix quality parameter

This generates output with bitrates similar to libvorbis for a given quality
value.

libavcodec/vorbisenc.c

@@ -1181,9 +1181,9 @@ static av_cold int vorbis_encode_init(AVCodecContext *avccontext)
         goto error;
 
     if (avccontext->flags & CODEC_FLAG_QSCALE)
-        venc->quality = avccontext->global_quality / (float)FF_QP2LAMBDA / 10.;
+        venc->quality = avccontext->global_quality / (float)FF_QP2LAMBDA;
     else
-        venc->quality = 0.03;
+        venc->quality = 3.0;
     venc->quality *= venc->quality;
 
     if ((ret = put_main_header(venc, (uint8_t**)&avccontext->extradata)) < 0)