fate: try to fix fate-nellymoser-aref-encode make dependancies

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

tests/fate/audio.mak

@@ -35,7 +35,7 @@ fate-nellymoser: CMP = oneoff
 fate-nellymoser: REF = $(SAMPLES)/nellymoser/nellymoser.pcm
 
 FATE_SAMPLES_AUDIO += fate-nellymoser-aref-encode
-fate-nellymoser-aref-encode: $(AREF)
+fate-nellymoser-aref-encode: $(AREF) ./tests/data/asynth-16000-1.wav
 fate-nellymoser-aref-encode: CMD = enc_dec_pcm flv wav s16le $(REF) -c:a nellymoser
 fate-nellymoser-aref-encode: CMP = stddev
 fate-nellymoser-aref-encode: REF = ./tests/data/asynth-16000-1.wav