Merge pull request #665 from gosuri/master

Fix for #664, crashed due to ig.Attachements being 0

builtin/providers/aws/resource_aws_internet_gateway.go

@@ -59,7 +59,12 @@ func resourceAwsInternetGatewayRead(d *schema.ResourceData, meta interface{}) er
 	}
 
 	ig := igRaw.(*ec2.InternetGateway)
-	d.Set("vpc_id", ig.Attachments[0].VpcId)
+	if len(ig.Attachments) == 0 {
+		// Gateway exists but not attached to the VPC
+		d.Set("vpc_id", "")
+	} else {
+		d.Set("vpc_id", ig.Attachments[0].VpcId)
+	}
 
 	return nil
 }