docker: fix the test on the docker distribution

test/Makefile.inc

-# Time-stamp: <modified the 23/10/2019 (at 15:32) by Erwan Jahier>
+# Time-stamp: <modified the 27/01/2020 (at 22:40) by Erwan Jahier>
 
 DIR=../../_build/install/default
 
 sasa=$(DIR)/bin/sasa  -l 100
+sasa=sasa
 
 LIB=-package algo
 
-.PRECIOUS: .ml
+.PRECIOUS: %.ml
 %.ml: %.dot 
 	sasa -reg $<