BUG/MEDIUM: edge: avoid setting state until success (#221)

It was recently reported by @sloh-fastly that if a
`sigsci_edge_deployment` was created without a `sigsci_site` it appeared
to have been created within Terraform state. This caused some weird
inconsistencies and could lead to the below error:

```
Error: Provider produced inconsistent result after apply

When applying changes to sigsci_site.acme_nginx_waf["stg"], provider
"provider[\"registry.terraform.io/signalsciences/sigsci\"]" produced an
unexpected new value: Root resource was present, but now absent.

This is a bug in the provider, which should be reported in the provider's own
issue tracker.
```

Shu provided a thorough outline to reproduce, unfortunately I was not
able to reproduce. However, I was able to identify what I believe to be
happening. It seemed that even though the `sigsci_edge_deployment` was
failing it was being populated into the terraform.tfstate file with a
"tainted" status attached.

It was found that the provider was prematurely calling `d.SetId()`
without first checking if an error had occurred. This was causing
Terraform to believe that it at least partially succeeded warranting it
to be in a tainted state.

This commit moves `d.SetId()` to only be called if the calls to
`CreateOrUpdateEdgeDeployment()` and `CreateOrUpdateEdgeDeploymentService`
were sucessful.

This fixes the underlying issue and avoids populating the Terraform
state with tainted versions of `sigsci_edge_deployment` and
`sigsci_edge_deployment_service` if an error occurred.

provider/resource_edge_deployment.go

@@ -24,9 +24,15 @@ func resourceEdgeDeployment() *schema.Resource {
 func createOrUpdateEdgeDeployment(d *schema.ResourceData, m interface{}) error {
 	pm := m.(providerMetadata)
 
+	err := pm.Client.CreateOrUpdateEdgeDeployment(pm.Corp, d.Get("site_short_name").(string))
+
+	if err != nil {
+		return err
+	}
+
 	d.SetId(d.Get("site_short_name").(string))
 
-	return pm.Client.CreateOrUpdateEdgeDeployment(pm.Corp, d.Get("site_short_name").(string))
+	return nil
 }
 
 func readEdgeDeployment(d *schema.ResourceData, m interface{}) error {

provider/resource_edge_deployment_service.go

@@ -45,13 +45,19 @@ func resourceEdgeDeploymentService() *schema.Resource {
 func createOrUpdateEdgeDeploymentService(d *schema.ResourceData, m interface{}) error {
 	pm := m.(providerMetadata)
 
-	d.SetId(d.Get("fastly_sid").(string))
-
 	activateVersion := d.Get("activate_version").(bool)
-	return pm.Client.CreateOrUpdateEdgeDeploymentService(pm.Corp, d.Get("site_short_name").(string), d.Get("fastly_sid").(string), sigsci.CreateOrUpdateEdgeDeploymentServiceBody{
+	err := pm.Client.CreateOrUpdateEdgeDeploymentService(pm.Corp, d.Get("site_short_name").(string), d.Get("fastly_sid").(string), sigsci.CreateOrUpdateEdgeDeploymentServiceBody{
 		ActivateVersion: &activateVersion,
 		PercentEnabled:  d.Get("percent_enabled").(int),
 	})
+
+	if err != nil {
+		return err
+	}
+
+	d.SetId(d.Get("fastly_sid").(string))
+
+	return nil
 }
 
 func readEdgeDeploymentService(d *schema.ResourceData, m interface{}) error {