Add new config option to allow setting virtual machine hardware version (#65)

* Add new config option to allow setting virtual machine hardware version

The vsphere-iso builder gets a new configuration option named
vm_version. It allows setting the VMWare virtual machine hardware
version to a non-default value.

The default behavior remains unchanged. Use the latest supported
hardware version that ESXi/vCenter allows.

VMWare KB for supported virtual machine hardware versions.

https://kb.vmware.com/s/article/1003746

* Change vm_version from string to int

driver/vm.go

@@ -53,6 +53,7 @@ type CreateConfig struct {
 	Network       string // "" for default network
 	NetworkCard   string // example: vmxnet3
 	USBController bool
+	Version       int // example: 10
 }
 
 func (d *Driver) NewVM(ref *types.ManagedObjectReference) *VirtualMachine {
@@ -396,6 +397,9 @@ func (config CreateConfig) toConfigSpec() types.VirtualMachineConfigSpec {
 	confSpec.Name = config.Name
 	confSpec.Annotation = config.Annotation
 	confSpec.GuestId = config.GuestOS
+	if config.Version != 0 {
+		confSpec.Version = fmt.Sprintf("%s%d", "vmx-", config.Version)
+	}
 	return confSpec
 }
 

iso/step_create.go

@@ -19,6 +19,7 @@ type CreateConfig struct {
 	Network       string `mapstructure:"network"`
 	NetworkCard   string `mapstructure:"network_card"`
 	USBController bool   `mapstructure:"usb_controller"`
+	Version       int    `mapstructure:"vm_version"`
 }
 
 func (c *CreateConfig) Prepare() []error {
@@ -31,6 +32,10 @@ func (c *CreateConfig) Prepare() []error {
 	errs = append(errs, tmp.VMConfig.Prepare()...)
 	errs = append(errs, tmp.HardwareConfig.Prepare()...)
 
+	if tmp.Version < 0 {
+		errs = append(errs, fmt.Errorf("'vm_version' cannot be a negative number"))
+	}
+
 	if len(errs) > 0 {
 		return errs
 	}
@@ -71,6 +76,7 @@ func (s *StepCreateVM) Run(state multistep.StateBag) multistep.StepAction {
 		Network:             s.Config.Network,
 		NetworkCard:         s.Config.NetworkCard,
 		USBController:       s.Config.USBController,
+		Version:             s.Config.Version,
 	})
 
 	if err != nil {