provider/aws: Add some tests for the Import for aws_eip

The Read func of the EIP has changed to set the `vpc` boolean value on
the response object having an Address. This is required as an EIP that
was specified, without a domain and then imported, would cause a
perpetual plan.

```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSEIP_'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2016/09/23 09:28:32 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSEIP_ -timeout
120m
=== RUN   TestAccAWSEIP_importEc2Classic
--- PASS: TestAccAWSEIP_importEc2Classic (116.16s)
=== RUN   TestAccAWSEIP_importVpc
--- PASS: TestAccAWSEIP_importVpc (61.89s)
=== RUN   TestAccAWSEIP_basic
--- PASS: TestAccAWSEIP_basic (18.86s)
=== RUN   TestAccAWSEIP_instance
--- PASS: TestAccAWSEIP_instance (185.95s)
=== RUN   TestAccAWSEIP_network_interface
--- PASS: TestAccAWSEIP_network_interface (63.20s)
=== RUN   TestAccAWSEIP_twoEIPsOneNetworkInterface
--- PASS: TestAccAWSEIP_twoEIPsOneNetworkInterface (65.64s)
=== RUN   TestAccAWSEIP_associated_user_private_ip
--- PASS: TestAccAWSEIP_associated_user_private_ip (201.34s)
PASS
ok      github.com/hashicorp/terraform/builtin/providers/aws    713.072s
```

builtin/providers/aws/resource_aws_eip.go

@@ -29,6 +29,7 @@ func resourceAwsEip() *schema.Resource {
 				Type:     schema.TypeBool,
 				Optional: true,
 				ForceNew: true,
+				Computed: true,
 			},
 
 			"instance": &schema.Schema{
@@ -168,7 +169,7 @@ func resourceAwsEipRead(d *schema.ResourceData, meta interface{}) error {
 
 	// On import (domain never set, which it must've been if we created),
 	// set the 'vpc' attribute depending on if we're in a VPC.
-	if _, ok := d.GetOk("domain"); !ok {
+	if address.Domain != nil {
 		d.Set("vpc", *address.Domain == "vpc")
 	}
 

builtin/providers/aws/resource_aws_eip_test.go

@@ -2,6 +2,7 @@ package aws
 
 import (
 	"fmt"
+	"os"
 	"strings"
 	"testing"
 
@@ -12,6 +13,50 @@ import (
 	"github.com/hashicorp/terraform/terraform"
 )
 
+func TestAccAWSEIP_importEc2Classic(t *testing.T) {
+	oldvar := os.Getenv("AWS_DEFAULT_REGION")
+	os.Setenv("AWS_DEFAULT_REGION", "us-east-1")
+	defer os.Setenv("AWS_DEFAULT_REGION", oldvar)
+
+	resourceName := "aws_eip.bar"
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSEIPDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAWSEIPInstanceEc2Classic,
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
+func TestAccAWSEIP_importVpc(t *testing.T) {
+	resourceName := "aws_eip.bar"
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSEIPDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAWSEIPNetworkInterfaceConfig,
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
 func TestAccAWSEIP_basic(t *testing.T) {
 	var conf ec2.Address
 
@@ -152,7 +197,7 @@ func testAccCheckAWSEIPDestroy(s *terraform.State) error {
 			describe, err := conn.DescribeAddresses(req)
 			if err != nil {
 				// Verify the error is what we want
-				if ae, ok := err.(awserr.Error); ok && ae.Code() == "InvalidAllocationID.NotFound" {
+				if ae, ok := err.(awserr.Error); ok && ae.Code() == "InvalidAllocationID.NotFound" || ae.Code() == "InvalidAddress.NotFound" {
 					continue
 				}
 				return err
@@ -168,7 +213,7 @@ func testAccCheckAWSEIPDestroy(s *terraform.State) error {
 			describe, err := conn.DescribeAddresses(req)
 			if err != nil {
 				// Verify the error is what we want
-				if ae, ok := err.(awserr.Error); ok && ae.Code() == "InvalidAllocationID.NotFound" {
+				if ae, ok := err.(awserr.Error); ok && ae.Code() == "InvalidAllocationID.NotFound" || ae.Code() == "InvalidAddress.NotFound" {
 					continue
 				}
 				return err
@@ -256,6 +301,20 @@ resource "aws_eip" "bar" {
 }
 `
 
+const testAccAWSEIPInstanceEc2Classic = `
+provider "aws" {
+	region = "us-east-1"
+}
+resource "aws_instance" "foo" {
+	ami = "ami-5469ae3c"
+	instance_type = "m1.small"
+}
+
+resource "aws_eip" "bar" {
+	instance = "${aws_instance.foo.id}"
+}
+`
+
 const testAccAWSEIPInstanceConfig = `
 resource "aws_instance" "foo" {
 	# us-west-2