ZMQ_SNDHWM and ZMQ_RCVHWM should use type of int instead of uint64_t

ZEROMQ设置ZMQ_SNDHWM、ZMQ_RCVHWM socket，提示 'invalid argument' 。

查看源码，setsockopt 在options.cpp：65中，ZMQ_SNDHWM、ZMQ_RCVHWM 类型是int，而在binding.cc中是unit64_t

setting ZMQ_SNDHWM and ZMQ_RCVHWM for the zmq socket so I looked into the zmq source and found that setsockopt in options.cpp:65, ZMQ_SNDHWM and ZMQ_RCVHWM is of type int but is uint64_t in binding.cc.