resource/aws_ec2_client_vpn_endpoint: Properly set status value into …

…Terraform state

Reference: #9954

Previously:

```
/Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_ec2_client_vpn_endpoint.go:226:18: R004: ResourceData.Set() incompatible value type: *github.com/aws/aws-sdk-go/service/ec2.ClientVpnEndpointStatus
```

Output from acceptance testing:

```
--- PASS: TestAccAwsEc2ClientVpnEndpoint_basic (21.32s)
```

aws/resource_aws_ec2_client_vpn_endpoint.go

@@ -223,7 +223,11 @@ func resourceAwsEc2ClientVpnEndpointRead(d *schema.ResourceData, meta interface{
 	d.Set("server_certificate_arn", result.ClientVpnEndpoints[0].ServerCertificateArn)
 	d.Set("transport_protocol", result.ClientVpnEndpoints[0].TransportProtocol)
 	d.Set("dns_name", result.ClientVpnEndpoints[0].DnsName)
-	d.Set("status", result.ClientVpnEndpoints[0].Status)
+
+	if result.ClientVpnEndpoints[0].Status != nil {
+		d.Set("status", result.ClientVpnEndpoints[0].Status.Code)
+	}
+
 	d.Set("split_tunnel", result.ClientVpnEndpoints[0].SplitTunnel)
 
 	err = d.Set("authentication_options", flattenAuthOptsConfig(result.ClientVpnEndpoints[0].AuthenticationOptions))

aws/resource_aws_ec2_client_vpn_endpoint_test.go

@@ -86,6 +86,7 @@ func TestAccAwsEc2ClientVpnEndpoint_basic(t *testing.T) {
 					testAccCheckAwsEc2ClientVpnEndpointExists("aws_ec2_client_vpn_endpoint.test"),
 					resource.TestCheckResourceAttr("aws_ec2_client_vpn_endpoint.test", "authentication_options.#", "1"),
 					resource.TestCheckResourceAttr("aws_ec2_client_vpn_endpoint.test", "authentication_options.0.type", "certificate-authentication"),
+					resource.TestCheckResourceAttr("aws_ec2_client_vpn_endpoint.test", "status", ec2.ClientVpnEndpointStatusCodePendingAssociate),
 				),
 			},