Fixes#8597
There was sometimes an issue where Terraform was deleting the ECR
repository from the statefile before the reposity was actually deleted.
Added retry logic for Terraform to wait for the repository to be deleted
before proceeding with the statefile update
```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSEcrRepository_'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2016/09/26 12:46:57 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v
-run=TestAccAWSEcrRepository_ -timeout 120m
=== RUN TestAccAWSEcrRepository_importBasic
--- PASS: TestAccAWSEcrRepository_importBasic (17.86s)
=== RUN TestAccAWSEcrRepository_basic
--- PASS: TestAccAWSEcrRepository_basic (16.40s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws 34.288s
```
Changes required:
* ECR Read func doesn't need to take ``registry_id` as it uses the
current account Id
* `name` wasn't being set in the ECR Read so the import was failing as
name wasn't found
```
make testacc TEST=./builtin/providers/aws
TESTARGS='-run=TestAccAWSEcrRepository_'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /vendor/)
TF_ACC=1 go test ./builtin/providers/aws -v
-run=TestAccAWSEcrRepository_ -timeout 120m
=== RUN TestAccAWSEcrRepository_importBasic
--- PASS: TestAccAWSEcrRepository_importBasic (17.37s)
=== RUN TestAccAWSEcrRepository_basic
--- PASS: TestAccAWSEcrRepository_basic (16.05s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws 33.437s
```