Salt masterless provisionner is  missing an option to upload a specific minion.conf

The minion.conf is the core configuration for salt stack node, for now the default one set by the bootstrap is used.

I thought initially that I could be sorting things out by using the file provisioner but at this stage the bootstrap hasn't been done and after it's too late.

I check the source and it seem straightforward to add. I will look to attach a PR to this issue.

If there is any question about this issues, let me know but I may delay a bit to answer as I'm living on the GMT/London.