provider/aws: Add support for importing Kinesis Streams (hashicorp#14278

)

Fixes: hashicorp#14260

```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSKinesisStream_import'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2017/05/08 10:32:47 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSKinesisStream_import -timeout 120m
=== RUN   TestAccAWSKinesisStream_importBasic
--- PASS: TestAccAWSKinesisStream_importBasic (101.93s)
PASS
ok  	github.com/hashicorp/terraform/builtin/providers/aws	101.978s
```

r/kinesis_stream.html.markdown

@@ -53,6 +53,15 @@ when creating a Kinesis stream. See [Amazon Kinesis Streams][2] for more.
 * `arn` - The Amazon Resource Name (ARN) specifying the Stream
 
 
+## Import
+
+Kinesis Streams can be imported using the `name`, e.g.
+
+```
+$ terraform import aws_kinesis_stream.test_stream terraform-kinesis-test
+```
+
 [1]: https://aws.amazon.com/documentation/kinesis/
 [2]: https://docs.aws.amazon.com/kinesis/latest/dev/amazon-kinesis-streams.html
 [3]: https://docs.aws.amazon.com/streams/latest/dev/monitoring-with-cloudwatch.html
+