Bump netty to 4.0.43

Bump netty to 4.0.43

http://netty.io/news/2016/07/01/4-0-38-Final-4-1-2-Final.html
http://netty.io/news/2016/07/15/4-0-39-Final-4-1-3-Final.html
http://netty.io/news/2016/07/27/4-0-40-Final-4-1-4-Final.html
http://netty.io/news/2016/08/29/4-0-41-Final-4-1-5-Final.html
http://netty.io/news/2016/10/14/4-0-42-Final-4-1-6-Final.html
http://netty.io/news/2017/01/12/4-0-43-Final-4-1-7-Final.html

Change-Id: Ib9bd686dbb645128a093f4f934710e19ba6e3fca
Signed-off-by: Robert Varga <rovarga@cisco.com>
Signed-off-by: Stephen Kitt <skitt@redhat.com>