deleted state
Fixes#7859
When a VPN Gateway has been manually deleted, we should expect it to be
added back to the plan
```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSVpnGateway_'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSVpnGateway_
-timeout 120m
=== RUN TestAccAWSVpnGateway_importBasic
--- PASS: TestAccAWSVpnGateway_importBasic (247.94s)
=== RUN TestAccAWSVpnGateway_basic
--- PASS: TestAccAWSVpnGateway_basic (409.50s)
=== RUN TestAccAWSVpnGateway_reattach
--- PASS: TestAccAWSVpnGateway_reattach (211.33s)
=== RUN TestAccAWSVpnGateway_delete
--- PASS: TestAccAWSVpnGateway_delete (121.10s)
=== RUN TestAccAWSVpnGateway_tags
--- PASS: TestAccAWSVpnGateway_tags (125.38s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws
1115.274s
```
When VPC is detached from VPN gateway, its VpcAttachment stays in place
just with state changed to "detached". Since terraform was not checking
attachment state, it used to think VPC gateway was still attached.
Change the `RetryFunc` from a plain `error` return type to a
specialized `RetryError` which must decide whether it is
retryable or not.
Add `RetryableError` / `NonRetryableError` factory functions that
callers are meant to use to build up these errors.
This makes it eminently clear whether or not a given error is
retryable from inside the client code.
Goal here is to _not_ change any behavior, simply reflect the
existing behavior with the new, clearer, API.
This landed in aws-sdk-go yesterday, breaking the AWS provider in many places:
3c259c9586
Here, with much sedding, grepping, and manual massaging, we attempt to
catch Terraform up to the new `awserr.Error` interface world.
Paul Stack