server: use net.SplitHostPort
server: use net.SplitHostPort

Signed-off-by: ISHIDA Wataru <15703620d0b11e835ab4f34ebf88f2f40cce783e@lab.ntt.co.jp>

j-kato/gobgp,osrg/gobgp,fujita/gobgp,osrg/gobgp,Dipsingh/gobgp,YujiOshima/gobgp,YujiOshima/gobgp,a16/gobgp,tamihiro/gobgp,fujita/gobgp,fujita/gobgp,fujita/gobgp,a16/gobgp,a16/gobgp,h-naoto/gobgp,Dipsingh/gobgp,ramrunner/gobgp,a16/gobgp,ishidawataru/gobgp,h-naoto/gobgp,j-kato/gobgp,a16/gobgp,postfix/gobgp,postfix/gobgp,YujiOshima/gobgp,osrg/gobgp,h-naoto/gobgp,ishidawataru/gobgp,a16/gobgp,tamihiro/gobgp,tamihiro/gobgp,j-kato/gobgp,a16/gobgp,osrg/gobgp,ramrunner/gobgp,ishidawataru/gobgp,ramrunner/gobgp,postfix/gobgp,Dipsingh/gobgp,tamihiro/gobgp