Mark phony swscale_error target as such.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@9150 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

tests/Makefile

@@ -73,4 +73,4 @@ distclean clean:
 	rm -f $(addsuffix $(EXESUF),audiogen videogen rotozoom seek_test tiny_psnr)
 
 .PHONY: all fulltest test codectest libavtest test-server seektest
-.PHONY: mpeg4 mpeg ac3 snow snowll distclean clean
+.PHONY: mpeg4 mpeg ac3 snow snowll swscale_error distclean clean