VOL-1867 move simulated olt from voltha-go to voltha-simolt-adapter

Sourced from voltha-go commit 251a11c0ffe60512318a644cd6ce0dc4e12f4018

Change-Id: I8e7ee4da1fed739b3c461917301d2729a79307f5
diff --git a/vendor/go.etcd.io/etcd/clientv3/ready_wait.go b/vendor/go.etcd.io/etcd/clientv3/ready_wait.go
new file mode 100644
index 0000000..c6ef585
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/clientv3/ready_wait.go
@@ -0,0 +1,30 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package clientv3
+
+import "context"
+
+// TODO: remove this when "FailFast=false" is fixed.
+// See https://github.com/grpc/grpc-go/issues/1532.
+func readyWait(rpcCtx, clientCtx context.Context, ready <-chan struct{}) error {
+	select {
+	case <-ready:
+		return nil
+	case <-rpcCtx.Done():
+		return rpcCtx.Err()
+	case <-clientCtx.Done():
+		return clientCtx.Err()
+	}
+}