script: Fix boost/C++17 compile failure
script: Fix boost/C++17 compile failure

script/standard.cpp:297:48: error: temporary of type 'boost::static_visitor<CScript>' has protected destructor
    return boost::apply_visitor(CScriptVisitor{}, dest);
                                               ^
/usr/include/boost/variant/static_visitor.hpp:53:5: note: declared protected here
    ~static_visitor() = default;
    ^
1 error generated.


Former-commit-id: aed52a3179463430d258504e1a79e7b5e6b42952
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin