capv: mask sshd and remove static wait

This is a similar change to #893 - see this PR for more info.

Signed-off-by: Johanan Liebermann <jliebermann@microsoft.com>

images/capi/packer/ova/flatcar.json

@@ -1,6 +1,6 @@
 {
   "ansible_extra_vars": "guestinfo_datasource_slug={{user `guestinfo_datasource_slug`}} guestinfo_datasource_ref={{user `guestinfo_datasource_ref`}} guestinfo_datasource_script={{user `guestinfo_datasource_script`}} ansible_python_interpreter=/opt/bin/python",
-  "boot_command_prefix": "curl -sLo /tmp/ignition.json https://raw.githubusercontent.com/flatcar-linux/flatcar-packer-qemu/daba089c7cde0456008115a5c44f90676da6d590/ignition-builder.json<enter>sed -i \"s|BUILDERSSHAUTHKEY|{{user `ssh_public_key`}}|\" /tmp/ignition.json<enter>sudo flatcar-install -d /dev/sda -o vmware_raw -C {{user `channel_name`}} -V {{user `release_version`}} -i /tmp/ignition.json<enter>sudo reboot<enter><wait3m>",
+  "boot_command_prefix": "sudo systemctl mask sshd.socket --now<enter>curl -sLo /tmp/ignition.json https://raw.githubusercontent.com/flatcar-linux/flatcar-packer-qemu/daba089c7cde0456008115a5c44f90676da6d590/ignition-builder.json<enter>sed -i \"s|BUILDERSSHAUTHKEY|{{user `ssh_public_key`}}|\" /tmp/ignition.json<enter>sudo flatcar-install -d /dev/sda -o vmware_raw -C {{user `channel_name`}} -V {{user `release_version`}} -i /tmp/ignition.json<enter>sudo reboot<enter>",
   "boot_wait": "60s",
   "build_name": "flatcar-{{env `FLATCAR_CHANNEL`}}-{{env `FLATCAR_VERSION`}}",
   "channel_name": "{{env `FLATCAR_CHANNEL`}}",