tests/Makefile: Fix ffservertest dependencies

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

tests/Makefile

@@ -12,7 +12,7 @@ FFMPEG=ffmpeg$(PROGSSUF)$(EXESUF)
 $(AREF): CMP=
 
 ffservertest: export PROGSUF = $(PROGSSUF)
-ffservertest: ffserver$(PROGSSUF)$(EXESUF) tests/vsynth1/00.pgm tests/data/asynth1.sw
+ffservertest: ffserver$(PROGSSUF)$(EXESUF) ffmpeg$(PROGSSUF)$(EXESUF) tests/vsynth1/00.pgm tests/data/asynth1.sw
 	@echo
 	@echo "Unfortunately ffserver is broken and therefore its regression"
 	@echo "test fails randomly. Treat the results accordingly."