server: avoid deadlock
server: avoid deadlock

  toConfig() uses lock in itself.

tamihiro/gobgp,a16/gobgp,j-kato/gobgp,fujita/gobgp,tamihiro/gobgp,a16/gobgp,fujita/gobgp,osrg/gobgp,j-kato/gobgp,a16/gobgp,j-kato/gobgp,a16/gobgp,a16/gobgp,osrg/gobgp,fujita/gobgp,tamihiro/gobgp,a16/gobgp,tamihiro/gobgp,osrg/gobgp,fujita/gobgp,a16/gobgp,osrg/gobgp