bigtable: use localhost instead of 127.0.0.1

This will allow tests to run on ipv6 only hosts

Change-Id: I7e86d55e8e36cfb707183aa0914b4018804d52aa
Reviewed-on: https://code-review.googlesource.com/22090
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
diff --git a/bigtable/bttest/example_test.go b/bigtable/bttest/example_test.go
index 5cfc370..3725f28 100644
--- a/bigtable/bttest/example_test.go
+++ b/bigtable/bttest/example_test.go
@@ -28,7 +28,7 @@
 
 func ExampleNewServer() {
 
-	srv, err := bttest.NewServer("127.0.0.1:0")
+	srv, err := bttest.NewServer("localhost:0")
 
 	if err != nil {
 		log.Fatalln(err)
diff --git a/bigtable/bttest/inmem.go b/bigtable/bttest/inmem.go
index 6c74aba..afabd69 100644
--- a/bigtable/bttest/inmem.go
+++ b/bigtable/bttest/inmem.go
@@ -19,7 +19,7 @@
 
 To use a Server, create it, and then connect to it with no security:
 (The project/instance values are ignored.)
-	srv, err := bttest.NewServer("127.0.0.1:0")
+	srv, err := bttest.NewServer("localhost:0")
 	...
 	conn, err := grpc.Dial(srv.Addr, grpc.WithInsecure())
 	...
diff --git a/bigtable/export_test.go b/bigtable/export_test.go
index 978530b..888e4af 100644
--- a/bigtable/export_test.go
+++ b/bigtable/export_test.go
@@ -98,7 +98,7 @@
 
 // NewEmulatedEnv builds and starts the emulator based environment
 func NewEmulatedEnv(config IntegrationTestConfig) (*EmulatedEnv, error) {
-	srv, err := bttest.NewServer("127.0.0.1:0", grpc.MaxRecvMsgSize(200<<20), grpc.MaxSendMsgSize(100<<20))
+	srv, err := bttest.NewServer("localhost:0", grpc.MaxRecvMsgSize(200<<20), grpc.MaxSendMsgSize(100<<20))
 	if err != nil {
 		return nil, err
 	}
diff --git a/bigtable/retry_test.go b/bigtable/retry_test.go
index cbeb8d1..518ce3f 100644
--- a/bigtable/retry_test.go
+++ b/bigtable/retry_test.go
@@ -33,7 +33,7 @@
 )
 
 func setupFakeServer(opt ...grpc.ServerOption) (tbl *Table, cleanup func(), err error) {
-	srv, err := bttest.NewServer("127.0.0.1:0", opt...)
+	srv, err := bttest.NewServer("localhost:0", opt...)
 	if err != nil {
 		return nil, nil, err
 	}