Revert "provider/aws: Fix dependency violation with subnets and secur…

…ity groups"

This reverts commit 3d80057.

Rationale: There is no guarantee that waiting will resolve the
DependencyViolation. It's possible, perhaps likely, that the thing
preventing the subnet deletion was created by some other means -- by
another user, by a dynamic application, in another manifest, or that it
was created by this manifest but for some other reason failed to be
deleted.

In these cases, the retry behavior makes the user wait 5 minutes only to
receive the misleading error:

Error deleting subnet: timeout while waiting for state to become
'destroyed'

The obvious response to this is to try again, which yields another 5
minutes of waiting.

The previous behavior was to fail quickly with an error which exactly
described the problem. While this is mildly annoying, it's at least
apparent what is happening.

The situation the original commit was intended to address could be more
elegantly addressed by:

  - running Terraform a second time, or
  - explicitly declaring dependencies via the `depends_on` attribute.

builtin/providers/aws/resource_aws_subnet.go

@@ -159,38 +159,17 @@ func resourceAwsSubnetDelete(d *schema.ResourceData, meta interface{}) error {
 	conn := meta.(*AWSClient).ec2SDKconn
 
 	log.Printf("[INFO] Deleting subnet: %s", d.Id())
-	req := &ec2.DeleteSubnetInput{
-		SubnetID: aws.String(d.Id()),
-	}
 
-	wait := resource.StateChangeConf{
-		Pending:    []string{"pending"},
-		Target:     "destroyed",
-		Timeout:    5 * time.Minute,
-		MinTimeout: 1 * time.Second,
-		Refresh: func() (interface{}, string, error) {
-			_, err := conn.DeleteSubnet(req)
-			if err != nil {
-				if apiErr, ok := err.(aws.APIError); ok {
-					if apiErr.Code == "DependencyViolation" {
-						// There is some pending operation, so just retry
-						// in a bit.
-						return 42, "pending", nil
-					}
-
-					if apiErr.Code == "InvalidSubnetID.NotFound" {
-						return 42, "destroyed", nil
-					}
-				}
-
-				return 42, "failure", err
-			}
+	err := ec2conn.DeleteSubnet(&ec2.DeleteSubnetRequest{
+		SubnetID: aws.String(d.Id()),
+	})
 
-			return 42, "destroyed", nil
-		},
-	}
+	if err != nil {
+		ec2err, ok := err.(aws.APIError)
+		if ok && ec2err.Code == "InvalidSubnetID.NotFound" {
+			return nil
+		}
 
-	if _, err := wait.WaitForState(); err != nil {
 		return fmt.Errorf("Error deleting subnet: %s", err)
 	}