server: fix aca6fd6ad4409b4cb63682bff3c79fca8ca2800d regression
server: fix aca6fd6ad4409b4cb63682bff3c79fca8ca2800d regression

Fix the bug introduced by the following commit:

commit aca6fd6ad4409b4cb63682bff3c79fca8ca2800d
Author: ISHIDA Wataru <ishida.wataru@lab.ntt.co.jp>
Date:   Tue May 24 05:47:52 2016 +0000

server: refactoring for monitorbestchanged api. use watcher infra

The fix is a workaround. We need to rewrite monitor.go shortly to
remove the dependency of grpc from server package. So we fix this in a
cleaner way soon.

Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>

a16/gobgp,ramrunner/gobgp,tamihiro/gobgp,osrg/gobgp,a16/gobgp,fujita/gobgp,tamihiro/gobgp,fujita/gobgp,ishidawataru/gobgp,Dipsingh/gobgp,j-kato/gobgp,ishidawataru/gobgp,a16/gobgp,fujita/gobgp,a16/gobgp,fujita/gobgp,tamihiro/gobgp,a16/gobgp,ishidawataru/gobgp,osrg/gobgp,a16/gobgp,tamihiro/gobgp,osrg/gobgp,a16/gobgp,j-kato/gobgp,Dipsingh/gobgp,ramrunner/gobgp,ramrunner/gobgp,Dipsingh/gobgp,osrg/gobgp,j-kato/gobgp