added disk_size_gb to config for TestAccAzureRMManagedDisk_import
added disk_size_gb to config for TestAccAzureRMManagedDisk_import

thiagocaiubi/terraform-provider-azurerm,thiagocaiubi/terraform-provider-azurerm,sebastus/terraform-provider-azurerm,sebastus/terraform-provider-azurerm,abhijeetgaiha/terraform-provider-azurerm,sebastus/terraform-provider-azurerm,abhijeetgaiha/terraform-provider-azurerm,thiagocaiubi/terraform-provider-azurerm,abhijeetgaiha/terraform-provider-azurerm