resource/aws_iam_policy_attachment: Fixes for tfproviderlint R006 (#1…

…2043)

Reference: #11864

`RetryFunc` should only be used when logic has a retryable condition. In the case of working with the AWS Go SDK, it also arbitrarily restricts the automatic retrying logic of API calls to the timeout, which is generally undesired.

This particular case looks like the original intent was to verify via read-after-write that the appropriate write was persisted, however the logic errantly returned `return resource.NonRetryableError()` with `nil` when the role policy was not found, ending the `RetryFunc` without an actual error and never retrying on any condition.

Previously:

```
aws/resource_aws_iam_policy_attachment.go:220:53: R006: RetryFunc should include RetryableError() handling or be removed
```

Output from acceptance testing:

```
--- PASS: TestAccAWSIAMPolicyAttachment_Groups_RenamedGroup (22.54s)
--- PASS: TestAccAWSIAMPolicyAttachment_Users_RenamedUser (23.00s)
--- PASS: TestAccAWSIAMPolicyAttachment_Roles_RenamedRole (24.95s)
--- PASS: TestAccAWSIAMPolicyAttachment_basic (39.85s)
--- PASS: TestAccAWSIAMPolicyAttachment_paginatedEntities (242.04s)
```

aws/resource_aws_iam_policy_attachment.go

@@ -3,13 +3,10 @@ package aws
 import (
 	"fmt"
 	"log"
-	"strings"
-	"time"
 
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/service/iam"
-	"github.com/hashicorp/terraform-plugin-sdk/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/validation"
 )
@@ -216,39 +213,6 @@ func attachPolicyToRoles(conn *iam.IAM, roles []*string, arn string) error {
 		if err != nil {
 			return err
 		}
-
-		var attachmentErr = resource.Retry(2*time.Minute, func() *resource.RetryError {
-
-			input := iam.ListRolePoliciesInput{
-				RoleName: r,
-			}
-
-			attachedPolicies, err := conn.ListRolePolicies(&input)
-			if err != nil {
-				return resource.NonRetryableError(err)
-			}
-
-			if len(attachedPolicies.PolicyNames) > 0 {
-				var foundPolicy bool
-				for _, policyName := range attachedPolicies.PolicyNames {
-					if strings.HasSuffix(arn, *policyName) {
-						foundPolicy = true
-						break
-					}
-				}
-
-				if !foundPolicy {
-					return resource.NonRetryableError(err)
-				}
-			}
-
-			return nil
-		})
-
-		if attachmentErr != nil {
-			return attachmentErr
-		}
-
 	}
 	return nil
 }