Upgrade io.netty : netty-codec-http2 and netty-common to 4.1.39.Final

Upgrade io.netty : netty-codec-http2 and netty-common to 4.1.39.Final

These insecure dependencies are brought in by io.grpc:grpc-netty:1.17.1.
Override the io.netty dependencies and add exclusions where version is mandated.

Resulting dependencies in policy/models/models-interactions on master*
$ mvn dependency:tree -Dverbose| grep io.netty
[INFO] +- io.netty:netty-codec-http2:jar:4.1.39.Final:compile
[INFO] |  +- io.netty:netty-common:jar:4.1.39.Final:compile
[INFO] |  +- io.netty:netty-buffer:jar:4.1.39.Final:compile
[INFO] |  +- io.netty:netty-transport:jar:4.1.39.Final:compile
[INFO] |  |  \- io.netty:netty-resolver:jar:4.1.39.Final:compile
[INFO] |  +- io.netty:netty-codec:jar:4.1.39.Final:compile
[INFO] |  +- io.netty:netty-handler:jar:4.1.39.Final:compile
[INFO] |  \- io.netty:netty-codec-http:jar:4.1.39.Final:compile
[INFO] +- io.netty:netty-handler-proxy:jar:4.1.39.Final:compile
[INFO] |  \- io.netty:netty-codec-socks:jar:4.1.39.Final:compile
[INFO] |  +- io.netty:netty-codec-http2:jar:4.1.39.Final:provided
[INFO] |  |  +- io.netty:netty-common:jar:4.1.39.Final:provided
[INFO] |  |  +- io.netty:netty-buffer:jar:4.1.39.Final:provided
[INFO] |  |  +- io.netty:netty-transport:jar:4.1.39.Final:provided
[INFO] |  |  |  \- io.netty:netty-resolver:jar:4.1.39.Final:provided
[INFO] |  |  +- io.netty:netty-codec:jar:4.1.39.Final:provided
[INFO] |  |  +- io.netty:netty-handler:jar:4.1.39.Final:provided
[INFO] |  |  \- io.netty:netty-codec-http:jar:4.1.39.Final:provided
[INFO] |  +- io.netty:netty-handler-proxy:jar:4.1.39.Final:provided
[INFO] |  |  \- io.netty:netty-codec-socks:jar:4.1.39.Final:provided

Issue-ID: POLICY-2072
Signed-off-by: Rashmi Pujar <rashmi.pujar@bell.ca>
Change-Id: Ib3706e1c67e33fe73ebbfc80a6b474021b4a2679