remove calls to removed def constructor

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/qe/qe.cpp

@@ -2472,7 +2472,7 @@ namespace qe {
             for_each_expr(p, fml);
             return false;
         }
-        catch (found) {
+        catch (found const&) {
             return true;
         }
     }

src/qe/qe_mbp.cpp

@@ -487,7 +487,7 @@ public:
                 val = model(var);
                 sub.insert(var, val);
                 if (defs)
-                    defs->push_back(mbp::def(expr_ref(var, m), val));
+                    defs->push_back({expr_ref(var, m), val});
                 unsigned j = 0;
                 for (expr* f : fmls) {
                     sub(f, tmp);