I've disabled the Log4j2 Jenkins build for now

[Matt Sicker]

I’ve disabled the Jenkins build for Log4j2 as we’re already testing PRs via 
GitHub right now. Unless we can use a GitHub Action to publish snapshots, 
though, I’ll have to update our Jenkins build to simply do just that for the 
master and release-2.x branches. I believe we’ve talked about this in a few 
threads before about having redundant PR checks, so I’ve gone ahead and 
disabled the Jenkins checks at least.
—
Matt Sicker