Build fixes for hpx 1.4 onwards

# include <hpx/config/defines.hpp>

# if defined(DCA_HAVE_HPX_LOGGING) && !defined(NDEBUG)

//#  include <hpx/logging.hpp>

#  include <hpx/lcos/local/mutex.hpp>

#  include <hpx/synchronization/mutex.hpp>

#  include <mutex> // lock_guard

typedef std::mutex    log_mutex_type;

extern log_mutex_type log_mutex;