[hotfix, runtime] Downgrade to Netty version 4.0.27.Final
[hotfix, runtime] Downgrade to Netty version 4.0.27.Final

Netty versions >= 4.0.28.Final contain an improvement by Netty, which slices
a Netty buffer instead of doing a memory copy (https://github.com/netty/netty/issues/3704)
in the LengthFieldBasedFrameDecoder. In some situations, this interacts badly
with our Netty pipeline leading to OutOfMemory error.

To reproduce, run batch WordCount with a range partitioner and reasonably large
data.

twalthr/flink,fhueske/flink,tony810430/flink,gustavoanatoly/flink,rmetzger/flink,tony810430/flink,zohar-mizrahi/flink,yew1eb/flink,gyfora/flink,godfreyhe/flink,shaoxuan-wang/flink,apache/flink,zjureel/flink,sunjincheng121/flink,kl0u/flink,sunjincheng121/flink,gustavoanatoly/flink,zentol/flink,kl0u/flink,kl0u/flink,mtunique/flink,gustavoanatoly/flink,xccui/flink,DieBauer/flink,apache/flink,zjureel/flink,Xpray/flink,zjureel/flink,haohui/flink,ueshin/apache-flink,WangTaoTheTonic/flink,StephanEwen/incubator-flink,tillrohrmann/flink,twalthr/flink,bowenli86/flink,tony810430/flink,Xpray/flink,kl0u/flink,hwstreaming/flink,fanyon/flink,gyfora/flink,godfreyhe/flink,clarkyzl/flink,tillrohrmann/flink,ueshin/apache-flink,apache/flink,xccui/flink,clarkyzl/flink,mtunique/flink,zhangminglei/flink,godfreyhe/flink,rmetzger/flink,hwstreaming/flink,xccui/flink,lincoln-lil/flink,greghogan/flink,hongyuhong/flink,tony810430/flink,haohui/flink,mylog00/flink,fanyon/flink,bowenli86/flink,kaibozhou/flink,rmetzger/flink,twalthr/flink,apache/flink,zentol/flink,sunjincheng121/flink,fhueske/flink,lincoln-lil/flink,apache/flink,lincoln-lil/flink,mylog00/flink,shaoxuan-wang/flink,shaoxuan-wang/flink,PangZhi/flink,zhangminglei/flink,sunjincheng121/flink,twalthr/flink,ueshin/apache-flink,Xpray/flink,zimmermatt/flink,darionyaphet/flink,DieBauer/flink,shaoxuan-wang/flink,tzulitai/flink,zimmermatt/flink,fanzhidongyzby/flink,jinglining/flink,WangTaoTheTonic/flink,GJL/flink,aljoscha/flink,wwjiang007/flink,tzulitai/flink,hequn8128/flink,yew1eb/flink,rmetzger/flink,darionyaphet/flink,GJL/flink,godfreyhe/flink,haohui/flink,hongyuhong/flink,hequn8128/flink,zjureel/flink,fhueske/flink,greghogan/flink,aljoscha/flink,fanyon/flink,mbode/flink,DieBauer/flink,fanyon/flink,greghogan/flink,kl0u/flink,greghogan/flink,xccui/flink,zjureel/flink,StephanEwen/incubator-flink,zhangminglei/flink,zohar-mizrahi/flink,shaoxuan-wang/flink,mtunique/flink,kaibozhou/flink,gustavoanatoly/flink,tillrohrmann/flink,aljoscha/flink,jinglining/flink,GJL/flink,mylog00/flink,wwjiang007/flink,fanzhidongyzby/flink,darionyaphet/flink,gyfora/flink,zjureel/flink,bowenli86/flink,clarkyzl/flink,hequn8128/flink,aljoscha/flink,StephanEwen/incubator-flink,ueshin/apache-flink,gyfora/flink,godfreyhe/flink,GJL/flink,zhangminglei/flink,yew1eb/flink,zentol/flink,clarkyzl/flink,tzulitai/flink,mbode/flink,tony810430/flink,zimmermatt/flink,twalthr/flink,fhueske/flink,fanzhidongyzby/flink,wwjiang007/flink,lincoln-lil/flink,tony810430/flink,PangZhi/flink,jinglining/flink,kaibozhou/flink,ueshin/apache-flink,rmetzger/flink,sunjincheng121/flink,gyfora/flink,yew1eb/flink,hwstreaming/flink,fanyon/flink,DieBauer/flink,mtunique/flink,clarkyzl/flink,PangZhi/flink,tillrohrmann/flink,aljoscha/flink,tillrohrmann/flink,zentol/flink,zentol/flink,WangTaoTheTonic/flink,zjureel/flink,wwjiang007/flink,zimmermatt/flink,StephanEwen/incubator-flink,jinglining/flink,twalthr/flink,darionyaphet/flink,WangTaoTheTonic/flink,zohar-mizrahi/flink,yew1eb/flink,wwjiang007/flink,zohar-mizrahi/flink,greghogan/flink,bowenli86/flink,GJL/flink,mbode/flink,fanzhidongyzby/flink,mbode/flink,kaibozhou/flink,greghogan/flink,mtunique/flink,zentol/flink,hequn8128/flink,zimmermatt/flink,xccui/flink,godfreyhe/flink,wwjiang007/flink,tony810430/flink,godfreyhe/flink,Xpray/flink,mylog00/flink,haohui/flink,wwjiang007/flink,lincoln-lil/flink,xccui/flink,WangTaoTheTonic/flink,gyfora/flink,kl0u/flink,gyfora/flink,darionyaphet/flink,tillrohrmann/flink,GJL/flink,jinglining/flink,kaibozhou/flink,StephanEwen/incubator-flink,hongyuhong/flink,hongyuhong/flink,tzulitai/flink,hequn8128/flink,twalthr/flink,gustavoanatoly/flink,zhangminglei/flink,PangZhi/flink,fhueske/flink,xccui/flink,DieBauer/flink,bowenli86/flink,lincoln-lil/flink,lincoln-lil/flink,Xpray/flink,hongyuhong/flink,mylog00/flink,jinglining/flink,mbode/flink,aljoscha/flink,rmetzger/flink,shaoxuan-wang/flink,tzulitai/flink,hwstreaming/flink,apache/flink,PangZhi/flink,hequn8128/flink,zohar-mizrahi/flink,rmetzger/flink,hwstreaming/flink,sunjincheng121/flink,StephanEwen/incubator-flink,tillrohrmann/flink,apache/flink,fanzhidongyzby/flink,fhueske/flink,zentol/flink,haohui/flink,bowenli86/flink,tzulitai/flink,kaibozhou/flink