Urd aborts if unrecognized options are passed in command line

When starting the urd daemon with an invalid option, the daemon simply aborts:

$ ./urd -e
terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::program_options::unknown_option> >'
  what():  unrecognised option '-e'
Aborted (core dumped)