Computername fix

[vbauzys]

Ref: https://github.com/terraform-providers/terraform-provider-vcd/issues/273

This is fix for an issue. Overall decision was made to introduce new parameter computer_name which explicitly sets computer name for VM. Existing implementation was left for back compatibility where computer name was set using name, but only when initscript was provided.
Also to help our customer warning message was added.
Note: Read haven't be added as Giuseppe is working on read, datasource and import capabilities.

[dataclouder]

Some questions for now.

[Didainius]

Only one question. So does it change the computer name automatically or is it needed to set customization.force = true

[Didainius]

Suggested change

	* `resource/vcd_vapp_vm` have new field `computer_name` [#334]
	* `resource/vcd_vapp_vm` has new field `computer_name` [#334]

[lvirbalas]

This comment is about the whole 318:343 approach. As it is right now, we're mixing the old behaviour with the new one, but I believe we should be prioritising new behaviour and leaving the old logic intact. In other words, we can simplify as follows:

1. Leave old code intact, only add a warning message inside it:

	if initScript, ok := d.GetOk("initscript"); ok {
			task, err := vm.RunCustomizationScript(d.Get("name").(string), initScript.(string))
			if err != nil {
				return fmt.Errorf("error with init script setting: %#v", err)
			}
			err = task.WaitTaskCompletion()
			if err != nil {
				return fmt.Errorf(errorCompletingTask, err)
			}

2. Remove "else" and just do this part if the new computer_name is defined:

	} else { // Remove and check for computer_name instead
			task, err := vm.Customize(computerName, "", false)
			if err != nil {
				return fmt.Errorf("error with applying computer name: %#v", err)
			}
			err = task.WaitTaskCompletion()
			if err != nil {
				return fmt.Errorf(errorCompletingTask, err)
			}

So, if the user defines the new computer_name we don't care about old way of setting it. If they don't, we use the old code without modifications and print a warning.

CC: @Didainius @dataclouder

[vbauzys]

Don't forget we need to leave initscript intact! And with your proposal we would overwrite initscript to "".

[lvirbalas]

No, because:
"} else { // Remove and check for computer_name instead"
Idea is that you set computer_name only if it's defined. If it's undefined, you don't "overwrite" the old logic.

[vbauzys]

With current API, to change computer_name you have to provide initscript - what's why it's implemented as it is now. In general all logic is left - no previous behaviour is removed - it works as it was working.

[Didainius]

I think @lvirbalas is right. The else block will always be triggered now and VMname will always be set.

[vbauzys]

Yep, for this case I added change

[lvirbalas]

LGTM now!

[Didainius]

Test suite and individual tests pass for me (the ones which were failing before)

[dataclouder]

LGTM

[lvirbalas]

The user reported an issue #338 with this implementation which is being fixed in #347