v2.3.9 quick update

[wdauchy]

Hello,

We might want to quickly update to v2.3.9 http://git.haproxy.org/?p=haproxy-2.3.git;a=commit;h=53945bf8cde846893bfb9a32e31b40ca9eab4310 there is an annoying bug with sticky tables potentially affecting many people

[wdauchy]

cc @tianon

[tianon]

Appreciate the heads up! I've kicked the automation now. 👍