devel/kaptain: Fix build with Clang 6

communication.cpp:108:32: error: invalid operands to binary expression ('__bind<int &, sockaddr *, unsigned int>' and 'int')

sizeof (struct sockaddr)) == -1)
~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~

http://beefy11.nyi.freebsd.org/data/head-i386-default/p477696_s338122/logs/errors/kaptain-0.73.log