Set the option '--server' of tests/tcp_sctp_client to be required
Set the option '--server' of tests/tcp_sctp_client to be required

If we run tcp_sctp_client without any options, the following error will occur:
[root@localhost seastar]# ./build/release/tests/tcp_sctp_client
program failed with uncaught exception: boost::bad_any_cast: failed conversion using boost::any_cast

In order to promp users to set the option '--server', we set '--server' as a required option, and it will prompt the following information when running it again:
[root@localhost seastar]# ./build/release/tests/tcp_sctp_client
terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::program_options::required_option> >'
  what():  the option '--server' is required but missing

Ref:
http://stackoverflow.com/questions/15535180/how-to-solve-boostbad-any-cast-failed-conversion-using-boostany-cast-when

Signed-off-by: Javeme Lee <5b97b9868f1a149f5b5e2367047bee73ec144685@gmail.com>
Message-Id: <20170123074731.83221-1-5b97b9868f1a149f5b5e2367047bee73ec144685@gmail.com>

cloudius-systems/seastar,avikivity/seastar,avikivity/seastar,avikivity/seastar,scylladb/seastar,dreamsxin/seastar,cloudius-systems/seastar,dreamsxin/seastar,scylladb/seastar,scylladb/seastar,dreamsxin/seastar,syuu1228/seastar,syuu1228/seastar,syuu1228/seastar,cloudius-systems/seastar