Fix a bug in the -ec mode where non-infix op were printed in their long version

e.g., "uminus" instead of "-"

src/licDump.ml

-(* Time-stamp: <modified the 17/04/2013 (at 11:10) by Erwan Jahier> *)
+(* Time-stamp: <modified the 17/04/2013 (at 11:23) by Erwan Jahier> *)
 
 open Lv6errors
 open Printf
@@ -375,7 +375,7 @@ and (string_of_by_pos_op_eff: Lic.by_pos_op srcflagged -> Lic.val_exp list -> st
                 | _ -> assert false
             ) 
             else 
-              (op_str ^
+              (op_short_str ^
                  (match op_str with
                    | "not" | "true" | "false"  ->  tuple vel
                    | _ -> tuple_par vel 

test/lus2lic.sum

-Test Run By jahier on Wed Apr 17 10:59:56 2013
+Test Run By jahier on Wed Apr 17 11:26:21 2013
 Native configuration is i686-pc-linux-gnu
 
 		=== lus2lic tests ===

test/lus2lic.time

-testcase ./lus2lic.tests/non-reg.exp completed in 25 seconds
+testcase ./lus2lic.tests/non-reg.exp completed in 60 seconds
 testcase ./lus2lic.tests/progression.exp completed in 0 seconds