[lib] CLUnfolder: Fix error during the init of __invariant_constraints with...

[lib] CLUnfolder: Fix error during the init of __invariant_constraints with dimacs data from query: extend instead of append

library/cadbiom/models/clause_constraints/mcl/CLUnfolder.py

@@ -1112,8 +1112,7 @@ class CLUnfolder(object):
 
         if self.__dimacs_invariant:
             # Add DIMACS aux clauses initial properties
-            ## TODO: pas de append ? tester avec... => aucun changement, pas de test unitaire ici...
-            self.__invariant_constraints += self.__dimacs_invariant
+            self.__invariant_constraints.append(self.__dimacs_invariant)
 
     def __init_variant_constraints_0(self):
         """Code variant constraints in a numerical clause.