speex: fix occasional buffer overflow

(VLC simply lost one sample - no memory errors.)

modules/audio_filter/resampler/speex.c

@@ -111,7 +111,7 @@ static block_t *Resample (filter_t *filter, block_t *in)
     const unsigned orate = filter->fmt_out.audio.i_rate;
 
     spx_uint32_t ilen = in->i_nb_samples;
-    spx_uint32_t olen = ((ilen + 1) * orate) / irate;
+    spx_uint32_t olen = ((ilen + 2) * orate) / irate;
 
     block_t *out = block_Alloc (olen * framesize);
     if (unlikely(out == NULL))