update etcd to 3.4.0rc2 (#3214)

This moves the entire etcd to go.etcd.io, so that it compiles cleanly
when using bazel.

Fixes: #3087
Signed-off-by: Miek Gieben <miek@miek.nl>

go.mod

@@ -16,23 +16,17 @@ require (
 	github.com/coredns/federation v0.0.0-20190818181423-e032b096babe
 	github.com/coreos/bbolt v1.3.2 // indirect
 	github.com/coreos/etcd v3.3.15+incompatible
-	github.com/coreos/go-semver v0.2.0 // indirect
 	github.com/coreos/go-systemd v0.0.0-20190212144455-93d5ec2c7f76 // indirect
 	github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f // indirect
 	github.com/dnstap/golang-dnstap v0.0.0-20170829151710-2cf77a2b5e11
 	github.com/evanphx/json-patch v4.1.0+incompatible // indirect
 	github.com/farsightsec/golang-framestream v0.0.0-20181102145529-8a0cb8ba8710
-	github.com/gogo/protobuf v1.2.1 // indirect
 	github.com/golang/groupcache v0.0.0-20190129154638-5b532d6fd5ef // indirect
 	github.com/golang/protobuf v1.3.2
 	github.com/googleapis/gnostic v0.2.0 // indirect
 	github.com/gophercloud/gophercloud v0.0.0-20190307220656-fe1ba5ce12dd // indirect
-	github.com/grpc-ecosystem/go-grpc-middleware v1.0.0 // indirect
-	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0 // indirect
-	github.com/grpc-ecosystem/grpc-gateway v1.8.5 // indirect
 	github.com/grpc-ecosystem/grpc-opentracing v0.0.0-20180507213350-8e809c8a8645
 	github.com/imdario/mergo v0.3.7 // indirect
-	github.com/jonboulle/clockwork v0.1.0 // indirect
 	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.1
 	github.com/miekg/dns v1.1.16
@@ -45,17 +39,11 @@ require (
 	github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90
 	github.com/prometheus/common v0.6.0
 	github.com/sirupsen/logrus v1.4.2 // indirect
-	github.com/soheilhy/cmux v0.1.4 // indirect
-	github.com/spf13/pflag v1.0.3 // indirect
+	github.com/spf13/cobra v0.0.5 // indirect
 	github.com/tinylib/msgp v1.1.0 // indirect
 	github.com/tmc/grpc-websocket-proxy v0.0.0-20190109142713-0ad062ec5ee5 // indirect
-	github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2 // indirect
-	go.etcd.io/bbolt v1.3.2 // indirect
-	go.uber.org/atomic v1.3.2 // indirect
-	go.uber.org/multierr v1.1.0 // indirect
-	go.uber.org/zap v1.9.1 // indirect
+	go.etcd.io/etcd v0.0.0-20190823073701-67d0c21bb04c // indirect
 	golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4 // indirect
-	golang.org/x/net v0.0.0-20190628185345-da137c7871d7 // indirect
 	golang.org/x/sys v0.0.0-20190801041406-cbf593c0f2f3
 	golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7 // indirect
 	google.golang.org/api v0.9.0