packet/bgp: PEP-8 and Python3 fixes
packet/bgp: PEP-8 and Python3 fixes

Signed-off-by: Jason Kölker <68c46a606457643eab92053c1c05574abb26f861@koelker.net>
Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>

zangree/ryu,TakeshiTseng/ryu,zangree/ryu,shinpeimuraoka/ryu,iwaseyusuke/ryu,hisaharu/ryu,pichuang/ryu,fujita/ryu,shinpeimuraoka/ryu,fkakuma/ryu,hisaharu/ryu,iwaseyusuke/ryu,fkakuma/ryu,pichuang/ryu,osrg/ryu,pichuang/ryu,Tejas-Subramanya/RYU_MEC,hisaharu/ryu,TakeshiTseng/ryu,TakeshiTseng/ryu,fkakuma/ryu,lagopus/ryu-lagopus-ext,Tejas-Subramanya/RYU_MEC,zangree/ryu,zangree/ryu,iwaseyusuke/ryu,zangree/ryu,takahashiminoru/ryu,hisaharu/ryu,fujita/ryu,iwaseyusuke/ryu,TakeshiTseng/ryu,osrg/ryu,takahashiminoru/ryu,iwaseyusuke/ryu,TakeshiTseng/ryu,fujita/ryu,shinpeimuraoka/ryu,fujita/ryu,lagopus/ryu-lagopus-ext,osrg/ryu,fkakuma/ryu,shinpeimuraoka/ryu,gareging/SDN_Framework,lagopus/ryu-lagopus-ext,lagopus/ryu-lagopus-ext,takahashiminoru/ryu,gareging/SDN_Framework,pichuang/ryu,gareging/SDN_Framework,pichuang/ryu,Tejas-Subramanya/RYU_MEC,Tejas-Subramanya/RYU_MEC,osrg/ryu,takahashiminoru/ryu,gareging/SDN_Framework,hisaharu/ryu,gareging/SDN_Framework,fkakuma/ryu,fujita/ryu,takahashiminoru/ryu,Tejas-Subramanya/RYU_MEC,osrg/ryu,lagopus/ryu-lagopus-ext,shinpeimuraoka/ryu