Argument to Boost Milliseconds must be integral in Boost >= 1.67

[sarlinpe]

With the last version of Boost the compilation of bondcpp fails because of non-matching types in the call to boost::posix_time::milliseconds. See ros/roscpp_core#79.

[mikaelarguedas]

Thanks @skydes for the patch

boost 1.67 indeed requires an integer to be passed: https://github.com/boostorg/date_time/blob/8e1f2be36027c007ce6d06e0674576a3794829a5/include/boost/date_time/time_duration.hpp#L286

casting to int64_t works from 1.54 to 1.67: https://github.com/boostorg/date_time/blob/9bdee756083a150221170d1c097eb972a6b09a49/include/boost/date_time/time_duration.hpp#L279
so this can be merged in this branch 👍

[huangqinjin]

@skydes why not just ros::Duration::toBoost()

[sarlinpe]

@huangqinjin ros::Duration::toBoost() only returns a value in microseconds, not milliseconds.

[huangqinjin]

@skydes condition_.timed_wait(mutex_, wait_time.toBoost());