turn off http2 for TLS setups for now (#11523)

due to lots of issues with x/net/http2, as
well as the bundled h2_bundle.go in the go
runtime should be avoided for now.

https://github.com/golang/go/issues/23559
https://github.com/golang/go/issues/42534
https://github.com/golang/go/issues/43989
https://github.com/golang/go/issues/33425
https://github.com/golang/go/issues/29246

With collection of such issues present, it
make sense to remove HTTP2 support for now

cmd/http/server.go

@@ -191,7 +191,7 @@ func NewServer(addrs []string, handler http.Handler, getCert certs.GetCertificat
 			// TLS hardening
 			PreferServerCipherSuites: true,
 			MinVersion:               tls.VersionTLS12,
-			NextProtos:               []string{"h2", "http/1.1"},
+			NextProtos:               []string{"http/1.1", "h2"},
 		}
 		tlsConfig.GetCertificate = getCert
 	}