message: 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.
diff: @@ -294,7 +294,7 @@ public:
  CScript GetScriptForDestination(const CTxDestination& dest)
  {
  - return boost::apply_visitor(CScriptVisitor{}, dest);
  + return boost::apply_visitor(CScriptVisitor(), dest);
  }
  CScript GetScriptForRawPubKey(const CPubKey& pubKey)
  