When consul is restarted and an envoy that had already sent
DiscoveryRequests to the previous consul process sends a request to the
new process it doesn't respect the setting and never populates
DiscoveryRequest.Node for the life of the new consul process due to this
bug: https://github.com/envoyproxy/envoy/issues/9682Fixes#8430
Related changes:
- hard-fail the xDS connection attempt if the envoy version is known to be too old to be supported
- remove the RouterMatchSafeRegex proxy feature since all supported envoy versions have it
- stop using --max-obj-name-len (due to: envoyproxy/envoy#11740)
R.B. Boyer