fix ssh identity...

Newly added ssh commands were missing the flag -i to pass an
identity file. This means that those commands use different
settings then the provisioners and their connection blocks
around them.

While adding this parameter, I decided it would be cleanest
to add local.ssh_args.

locals.tf

@@ -11,6 +11,9 @@ locals {
   # if an ssh agent is used.
   ssh_identity_file = var.private_key == null ? var.public_key : var.private_key
 
+  # shared flags for ssh to ignore host keys, to use root and our ssh identity file for all connections during provisioning.
+  ssh_args = "-o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -l root -i ${local.ssh_identity_file}"
+
   MicroOS_install_commands = [
     "set -ex",
     "apt-get install -y aria2",