Update our Gerrit 3.9 image to 3.9.6 and our 3.10 image to 3.10.1. The
3.9.6 update is the one that will be deployed to production (3.10 is
only used for testing currently) and has the most relevant changes as a
result. The release notes for that release can be found here:
https://www.gerritcodereview.com/3.9.html
There are bugfixes and performance updates. Notably the replication
plugins sees some updates. I don't expect these updates to affect our
use of the replication plugin but we should be on the lookout for any
unexpected behavior changes with this plugin.
Change-Id: Ida223104076bb161443269335a43efeb1bdf40e3
715cfa709d