Add Service Bus scenario tests

WindowsAzure#883
WindowsAzure#895
WindowsAzure#893
WindowsAzure#894

- [x] Get-AzureSBLocation scenario tests
- [x] Get-AzureSBNamespace scenario tests
- [ ] Get-AzureSBNamespace with invalid name unit test
- [ ] New-AzureSBNamespace scenario tests
- [ ] Remove-AzureSBNamespace scenario tests
- [ ] Test-AzureName -ServiceBusNamespace scenario tests