Remove const qualifier in translator::run return type

* src/tgbaalgos/translate.cc, src/tgbaalgos/translate.hh: Remove const
qualifier in translator::run return type.

src/tgbaalgos/translate.cc

@@ -61,7 +61,7 @@ namespace spot
     simpl_owned_ = simpl_ = new ltl::ltl_simplifier(options, dict);
   }
 
-  const_tgba_digraph_ptr translator::run(const ltl::formula** f)
+  tgba_digraph_ptr translator::run(const ltl::formula** f)
   {
     const ltl::formula* r = simpl_->simplify(*f);
     (*f)->destroy();
@@ -91,7 +91,7 @@ namespace spot
     return aut;
   }
 
-  const_tgba_digraph_ptr translator::run(const ltl::formula* f)
+  tgba_digraph_ptr translator::run(const ltl::formula* f)
   {
     f->clone();
     auto aut = run(&f);

src/tgbaalgos/translate.hh

@@ -103,14 +103,14 @@ namespace spot
     ///
     /// The formula \a f is simplified internally, but it is not
     /// not destroyed (this is the responsibility of the caller).
-    const_tgba_digraph_ptr run(const ltl::formula* f);
+    tgba_digraph_ptr run(const ltl::formula* f);
 
     /// \brief Convert \a f into an automaton, and update f.
     ///
     /// The formula <code>*f</code> is destroyed, and replaced
     /// by the simplified version, which should be destroyed by
     /// the caller.
-    const_tgba_digraph_ptr run(const ltl::formula** f);
+    tgba_digraph_ptr run(const ltl::formula** f);
 
   protected:
     void setup_opt(const option_map* opt);