zebra: support of debug log for zapi
zebra: support of debug log for zapi

"PANIC=runtime error: index out of range", due to defining "ifindex" field.

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