provider/azurerm: Wait for `azurerm_storage_account` to be available (#7329)

Fixes #7005 where a container tried to provision *before* the storage
account was available. We now wait for the Storage Account to be in the
`Succeeded` state before returning

```
make testacc TEST=./builtin/providers/azurerm TESTARGS='-run=TestAccAzureRMStorageAccount_'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /vendor/)
TF_ACC=1 go test ./builtin/providers/azurerm -v
-run=TestAccAzureRMStorageAccount_ -timeout 120m
=== RUN   TestAccAzureRMStorageAccount_basic
--- PASS: TestAccAzureRMStorageAccount_basic (163.68s)
PASS
ok      github.com/hashicorp/terraform/builtin/providers/azurerm
163.695s
```

builtin/providers/azurerm/resource_arm_storage_account.go

@@ -2,11 +2,14 @@ package azurerm
 
 import (
 	"fmt"
+	"log"
 	"net/http"
 	"regexp"
 	"strings"
+	"time"
 
 	"github.com/Azure/azure-sdk-for-go/arm/storage"
+	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/helper/schema"
 )
 
@@ -109,7 +112,8 @@ func resourceArmStorageAccount() *schema.Resource {
 }
 
 func resourceArmStorageAccountCreate(d *schema.ResourceData, meta interface{}) error {
-	client := meta.(*ArmClient).storageServiceClient
+	client := meta.(*ArmClient)
+	storageClient := client.storageServiceClient
 
 	resourceGroupName := d.Get("resource_group_name").(string)
 	storageAccountName := d.Get("name").(string)
@@ -127,13 +131,13 @@ func resourceArmStorageAccountCreate(d *schema.ResourceData, meta interface{}) e
 		Tags:     expandTags(tags),
 	}
 
-	_, err := client.Create(resourceGroupName, storageAccountName, opts, make(chan struct{}))
+	_, err := storageClient.Create(resourceGroupName, storageAccountName, opts, make(chan struct{}))
 	if err != nil {
 		return fmt.Errorf("Error creating Azure Storage Account '%s': %s", storageAccountName, err)
 	}
 
 	// The only way to get the ID back apparently is to read the resource again
-	read, err := client.GetProperties(resourceGroupName, storageAccountName)
+	read, err := storageClient.GetProperties(resourceGroupName, storageAccountName)
 	if err != nil {
 		return err
 	}
@@ -142,6 +146,18 @@ func resourceArmStorageAccountCreate(d *schema.ResourceData, meta interface{}) e
 			storageAccountName, resourceGroupName)
 	}
 
+	log.Printf("[DEBUG] Waiting for Storage Account (%s) to become available", storageAccountName)
+	stateConf := &resource.StateChangeConf{
+		Pending:    []string{"Updating", "Creating"},
+		Target:     []string{"Succeeded"},
+		Refresh:    storageAccountStateRefreshFunc(client, resourceGroupName, storageAccountName),
+		Timeout:    30 * time.Minute,
+		MinTimeout: 15 * time.Second,
+	}
+	if _, err := stateConf.WaitForState(); err != nil {
+		return fmt.Errorf("Error waiting for Storage Account (%s) to become available: %s", storageAccountName, err)
+	}
+
 	d.SetId(*read.ID)
 
 	return resourceArmStorageAccountRead(d, meta)
@@ -305,3 +321,14 @@ func validateArmStorageAccountType(v interface{}, k string) (ws []string, es []e
 	es = append(es, fmt.Errorf("Invalid storage account type %q", input))
 	return
 }
+
+func storageAccountStateRefreshFunc(client *ArmClient, resourceGroupName string, storageAccountName string) resource.StateRefreshFunc {
+	return func() (interface{}, string, error) {
+		res, err := client.storageServiceClient.GetProperties(resourceGroupName, storageAccountName)
+		if err != nil {
+			return nil, "", fmt.Errorf("Error issuing read request in storageAccountStateRefreshFunc to Azure ARM for Storage Account '%s' (RG: '%s'): %s", storageAccountName, resourceGroupName, err)
+		}
+
+		return res, string(res.Properties.ProvisioningState), nil
+	}
+}