bgp: fix send_notificaiton crash
bgp: fix send_notificaiton crash

self._localname() is invalid before a connection establishes.

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

StephenKing/summerschool-2015-ryu,jalilm/ryu,umkcdcrg01/ryu_openflow,darjus-amzn/ryu,StephenKing/ryu,fujita/ryu,gopchandani/ryu,shinpeimuraoka/ryu,StephenKing/summerschool-2015-ryu,lsqtongxin/ryu,TakeshiTseng/ryu,shinpeimuraoka/ryu,Zouyiran/ryu,habibiefaried/ryu,StephenKing/summerschool-2015-ryu,gareging/SDN_Framework,alanquillin/ryu,lsqtongxin/ryu,lzppp/mylearning,shinpeimuraoka/ryu,lagopus/ryu-lagopus-ext,umkcdcrg01/ryu_openflow,takahashiminoru/ryu,elahejalalpour/ELRyu,diogommartins/ryu,ynkjm/ryu,alanquillin/ryu,pichuang/ryu,lsqtongxin/ryu,openvapour/ryu,lzppp/mylearning,hisaharu/ryu,elahejalalpour/ELRyu,openvapour/ryu,darjus-amzn/ryu,zyq001/ryu,diogommartins/ryu,zangree/ryu,zangree/ryu,Zouyiran/ryu,fkakuma/ryu,StephenKing/ryu,Zouyiran/ryu,pichuang/ryu,OpenState-SDN/ryu,habibiefaried/ryu,haniehrajabi/ryu,yamt/ryu,alanquillin/ryu,osrg/ryu,castroflavio/ryu,osrg/ryu,sivaramakrishnansr/ryu,John-Lin/ryu,diogommartins/ryu,habibiefaried/ryu,StephenKing/summerschool-2015-ryu,shinpeimuraoka/ryu,yamt/ryu,castroflavio/ryu,StephenKing/ryu,zangree/ryu,Zouyiran/ryu,evanscottgray/ryu,OpenState-SDN/ryu,iwaseyusuke/ryu,ysywh/ryu,alanquillin/ryu,openvapour/ryu,openvapour/ryu,yamt/ryu,osrg/ryu,evanscottgray/ryu,pichuang/ryu,muzixing/ryu,hisaharu/ryu,umkcdcrg01/ryu_openflow,gareging/SDN_Framework,darjus-amzn/ryu,elahejalalpour/ELRyu,fkakuma/ryu,darjus-amzn/ryu,muzixing/ryu,ttsubo/ryu,fujita/ryu,TakeshiTseng/ryu,lagopus/ryu-lagopus-ext,yamt/ryu,John-Lin/ryu,takahashiminoru/ryu,TakeshiTseng/ryu,jalilm/ryu,hisaharu/ryu,jalilm/ryu,jazzmes/ryu,jkoelker/ryu,hisaharu/ryu,diogommartins/ryu,alyosha1879/ryu,umkcdcrg01/ryu_openflow,iwaseyusuke/ryu,hisaharu/ryu,ynkjm/ryu,castroflavio/ryu,lagopus/ryu-lagopus-ext,sivaramakrishnansr/ryu,John-Lin/ryu,OpenState-SDN/ryu,gopchandani/ryu,alanquillin/ryu,Tesi-Luca-Davide/ryu,habibiefaried/ryu,TakeshiTseng/ryu,gopchandani/ryu,darjus-amzn/ryu,Zouyiran/ryu,Tejas-Subramanya/RYU_MEC,ttsubo/ryu,sivaramakrishnansr/ryu,yamt/ryu,fkakuma/ryu,gareging/SDN_Framework,pichuang/ryu,Tesi-Luca-Davide/ryu,haniehrajabi/ryu,alyosha1879/ryu,OpenState-SDN/ryu,haniehrajabi/ryu,ttsubo/ryu,muzixing/ryu,ttsubo/ryu,zyq001/ryu,gareging/SDN_Framework,ysywh/ryu,gopchandani/ryu,umkcdcrg01/ryu_openflow,iwaseyusuke/ryu,John-Lin/ryu,Tesi-Luca-Davide/ryu,ysywh/ryu,ysywh/ryu,fkakuma/ryu,zangree/ryu,lagopus/ryu-lagopus-ext,takahashiminoru/ryu,openvapour/ryu,Tesi-Luca-Davide/ryu,ynkjm/ryu,Tejas-Subramanya/RYU_MEC,zyq001/ryu,jalilm/ryu,jkoelker/ryu,haniehrajabi/ryu,alyosha1879/ryu,muzixing/ryu,osrg/ryu,lsqtongxin/ryu,TakeshiTseng/ryu,lsqtongxin/ryu,Tesi-Luca-Davide/ryu,Tejas-Subramanya/RYU_MEC,fujita/ryu,Tejas-Subramanya/RYU_MEC,lzppp/mylearning,OpenState-SDN/ryu,gareging/SDN_Framework,gopchandani/ryu,ttsubo/ryu,StephenKing/summerschool-2015-ryu,Tejas-Subramanya/RYU_MEC,ynkjm/ryu,shinpeimuraoka/ryu,diogommartins/ryu,osrg/ryu,takahashiminoru/ryu,fujita/ryu,evanscottgray/ryu,StephenKing/ryu,sivaramakrishnansr/ryu,elahejalalpour/ELRyu,zyq001/ryu,lzppp/mylearning,jalilm/ryu,takahashiminoru/ryu,zyq001/ryu,fujita/ryu,muzixing/ryu,ynkjm/ryu,haniehrajabi/ryu,alyosha1879/ryu,fkakuma/ryu,jazzmes/ryu,habibiefaried/ryu,lagopus/ryu-lagopus-ext,ysywh/ryu,lzppp/mylearning,pichuang/ryu,John-Lin/ryu,StephenKing/ryu,jkoelker/ryu,elahejalalpour/ELRyu,iwaseyusuke/ryu,zangree/ryu,iwaseyusuke/ryu,jazzmes/ryu,sivaramakrishnansr/ryu