Correct AWS VPC or route table read functions

If the state file contained a VPC or a route table which no longer
exists, Terraform would fail to create the correct plan, which is to
recreate them.

In the case of VPCs, this was due to incorrect error handling. The AWS
SDK returns a aws.APIError, not a *aws.APIError on error.  When the VPC
no longer exists, upon attempting to refresh state Terraform would
simply exit with an error.

For route tables, the provider would recognize that the route table no
longer existed, but would not make the appropriate call to update the
state as such. Thus there'd be no crash, but also no plan to re-create
the route table.

builtin/providers/aws/resource_aws_route_table.go

@@ -107,6 +107,7 @@ func resourceAwsRouteTableRead(d *schema.ResourceData, meta interface{}) error {
 		return err
 	}
 	if rtRaw == nil {
+		d.SetId("")
 		return nil
 	}
 

builtin/providers/aws/resource_aws_vpc.go

@@ -238,7 +238,7 @@ func resourceAwsVpcDelete(d *schema.ResourceData, meta interface{}) error {
 	}
 	log.Printf("[INFO] Deleting VPC: %s", d.Id())
 	if err := ec2conn.DeleteVPC(DeleteVpcOpts); err != nil {
-		ec2err, ok := err.(*aws.APIError)
+		ec2err, ok := err.(aws.APIError)
 		if ok && ec2err.Code == "InvalidVpcID.NotFound" {
 			return nil
 		}
@@ -258,7 +258,7 @@ func VPCStateRefreshFunc(conn *ec2.EC2, id string) resource.StateRefreshFunc {
 		}
 		resp, err := conn.DescribeVPCs(DescribeVpcOpts)
 		if err != nil {
-			if ec2err, ok := err.(*aws.APIError); ok && ec2err.Code == "InvalidVpcID.NotFound" {
+			if ec2err, ok := err.(aws.APIError); ok && ec2err.Code == "InvalidVpcID.NotFound" {
 				resp = nil
 			} else {
 				log.Printf("Error on VPCStateRefresh: %s", err)

builtin/providers/aws/resource_aws_vpc_test.go

@@ -132,7 +132,7 @@ func testAccCheckVpcDestroy(s *terraform.State) error {
 		}
 
 		// Verify the error is what we want
-		ec2err, ok := err.(*aws.APIError)
+		ec2err, ok := err.(aws.APIError)
 		if !ok {
 			return err
 		}