BUG-1132: upgrade netty to 4.0.19
BUG-1132: upgrade netty to 4.0.19

As per description in bugzilla, this bumps netty version to 4.0.19, such
that we get buffer pooling performance enhancements needed for
openflowjava.

Change-Id: I0fcb537c89dd4fce2bcc28c422993cb8980c5afa
Signed-off-by: Robert Varga <b8bd3df785fdc0ff42dd1710c5d91998513c57ef@cisco.com>

aryantaheri/monitoring-controller,my76128/controller,mandeepdhami/controller,mandeepdhami/controller,my76128/controller,aryantaheri/controller,mandeepdhami/controller,Sushma7785/OpenDayLight-Load-Balancer,aryantaheri/monitoring-controller,aryantaheri/controller,my76128/controller,tx1103mark/controller,tx1103mark/controller,Johnson-Chou/test,aryantaheri/monitoring-controller,aryantaheri/controller,inocybe/odl-controller,522986491/controller,tx1103mark/controller,mandeepdhami/controller,aryantaheri/monitoring-controller,inocybe/odl-controller,tx1103mark/controller,opendaylight/controller,Johnson-Chou/test,my76128/controller,522986491/controller,Sushma7785/OpenDayLight-Load-Balancer