Clean up server socket and thread when shutting down
Clean up server socket and thread when shutting down

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

shinpeimuraoka/ryu,lagopus/ryu-lagopus-ext,Tejas-Subramanya/RYU_MEC,takahashiminoru/ryu,John-Lin/ryu,zangree/ryu,sivaramakrishnansr/ryu,diogommartins/ryu,zangree/ryu,hisaharu/ryu,John-Lin/ryu,osrg/ryu,zyq001/ryu,alanquillin/ryu,diogommartins/ryu,pichuang/ryu,osrg/ryu,TakeshiTseng/ryu,fujita/ryu,zangree/ryu,iwaseyusuke/ryu,fkakuma/ryu,TakeshiTseng/ryu,Tejas-Subramanya/RYU_MEC,ttsubo/ryu,fujita/ryu,alanquillin/ryu,lagopus/ryu-lagopus-ext,StephenKing/ryu,lsqtongxin/ryu,gareging/SDN_Framework,lsqtongxin/ryu,ttsubo/ryu,shinpeimuraoka/ryu,elahejalalpour/ELRyu,OpenState-SDN/ryu,lagopus/ryu-lagopus-ext,gareging/SDN_Framework,zyq001/ryu,habibiefaried/ryu,fkakuma/ryu,takahashiminoru/ryu,pichuang/ryu,elahejalalpour/ELRyu,Zouyiran/ryu,sivaramakrishnansr/ryu,StephenKing/ryu,pichuang/ryu,alanquillin/ryu,osrg/ryu,OpenState-SDN/ryu,diogommartins/ryu,Tejas-Subramanya/RYU_MEC,elahejalalpour/ELRyu,sivaramakrishnansr/ryu,fujita/ryu,shinpeimuraoka/ryu,gareging/SDN_Framework,Zouyiran/ryu,TakeshiTseng/ryu,hisaharu/ryu,OpenState-SDN/ryu,fkakuma/ryu,OpenState-SDN/ryu,sivaramakrishnansr/ryu,osrg/ryu,takahashiminoru/ryu,John-Lin/ryu,lagopus/ryu-lagopus-ext,ttsubo/ryu,iwaseyusuke/ryu,habibiefaried/ryu,iwaseyusuke/ryu,habibiefaried/ryu,pichuang/ryu,zyq001/ryu,hisaharu/ryu,lagopus/ryu-lagopus-ext,fujita/ryu,lsqtongxin/ryu,fkakuma/ryu,ttsubo/ryu,John-Lin/ryu,darjus-amzn/ryu,Zouyiran/ryu,darjus-amzn/ryu,darjus-amzn/ryu,Zouyiran/ryu,darjus-amzn/ryu,diogommartins/ryu,StephenKing/ryu,darjus-amzn/ryu,elahejalalpour/ELRyu,Tejas-Subramanya/RYU_MEC,zyq001/ryu,zyq001/ryu,ttsubo/ryu,habibiefaried/ryu,shinpeimuraoka/ryu,lsqtongxin/ryu,lsqtongxin/ryu,iwaseyusuke/ryu,osrg/ryu,StephenKing/ryu,Tejas-Subramanya/RYU_MEC,alanquillin/ryu,sivaramakrishnansr/ryu,iwaseyusuke/ryu,shinpeimuraoka/ryu,alanquillin/ryu,Zouyiran/ryu,StephenKing/ryu,fujita/ryu,habibiefaried/ryu,hisaharu/ryu,pichuang/ryu,elahejalalpour/ELRyu,takahashiminoru/ryu,gareging/SDN_Framework,fkakuma/ryu,hisaharu/ryu,gareging/SDN_Framework,John-Lin/ryu,TakeshiTseng/ryu,OpenState-SDN/ryu,zangree/ryu,TakeshiTseng/ryu,takahashiminoru/ryu,diogommartins/ryu,zangree/ryu