Remove key vault policy from state iff it existed

This fixes the test added in the previous commit, while retaining the ability to
reflect access policy deletion by deleting the key vault itself.

azurerm/resource_arm_key_vault_access_policy.go

@@ -145,7 +145,11 @@ func resourceArmKeyVaultAccessPolicyCreateOrDelete(d *schema.ResourceData, meta
 
 	keyVault, err := client.Get(ctx, resourceGroup, vaultName)
 	if err != nil {
-		if utils.ResponseWasNotFound(keyVault.Response) {
+		// If the key vault does not exist but this is not a new resource, the policy
+		// which previously existed was deleted with the key vault, so reflect that in
+		// state. If this is a new resource and key vault does not exist, it's likely
+		// a bad ID was given.
+		if utils.ResponseWasNotFound(keyVault.Response) && !d.IsNewResource() {
 			log.Printf("[DEBUG] Parent Key Vault %q was not found in Resource Group %q - removing from state!", vaultName, resourceGroup)
 			d.SetId("")
 			return nil