This reverts commit 5131134c1d.
Well, that was a rather disappointing result. Turns out, DigitalOcean
adds PROXY lines to _all_ connections. I suppose that's to be expected.
However, what wasn't expected, was that ingress-nginx would only be
capable of handling them for HTTP/S traffic, and not TCP passthrough.
For that reason, we actually can't enable PROXY without instead using a
sidecar to eat the PROXY line.