Fixed dealloc of lobject->smode

I put it by mistake into the in the self->conn checked block in the
previous commit.

psycopg/lobject_type.c

@@ -359,8 +359,8 @@ lobject_dealloc(PyObject* obj)
         if (lobject_close(self) < 0)
             PyErr_Print();
         Py_XDECREF((PyObject*)self->conn);
-        PyMem_Free(self->smode);
     }
+    PyMem_Free(self->smode);
 
     Dprintf("lobject_dealloc: deleted lobject object at %p, refcnt = "
             FORMAT_CODE_PY_SSIZE_T, obj, Py_REFCNT(obj));