Update LogDog client to export its host.

logdog/client/coordinator/client.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package coordinator
 
 import (
         "github.com/luci/luci-go/common/auth"
         "github.com/luci/luci-go/grpc/prpc"
         "github.com/luci/luci-go/logdog/api/endpoints/coordinator/logs/v1"
         "github.com/luci/luci-go/logdog/common/types"
         "github.com/luci/luci-go/luci_config/common/cfgtypes"
 )
 
 var (
         // Scopes is the set of scopes needed for the Coordinator user endpoints.
         Scopes = []string{
                 auth.OAuthScopeEmail,
         }
 )
 
 // Client wraps a Logs client with user-friendly methods.
 //
 // Each method should operate independently, so calling methods from different
 // goroutines must not cause any problems.
 type Client struct {
         // C is the underlying LogsClient interface.
         C logdog.LogsClient
+        // Host is the LogDog host. This is loaded from the pRPC client in NewClient.
+        Host string
 }
 
 // NewClient returns a new Client instance bound to a pRPC Client.
 func NewClient(c *prpc.Client) *Client {
         return &Client{
-                C: logdog.NewLogsPRPCClient(c),
+                C:    logdog.NewLogsPRPCClient(c),
+                Host: c.Host,
         }
 }
 
 // Stream returns a Stream instance for the named stream.
 func (c *Client) Stream(project cfgtypes.ProjectName, path types.StreamPath) *Stream {
         return &Stream{
                 c:       c,
                 project: project,
                 path:    path,
         }
 }