Scripts using /bin/sh

The following scripts have to be interpreted with /bin/sh. This is not a
suitable language for writing even moderately complex programs with. For
example, it is fraught with edge cases, and automated testing is hard.
The latter is especially problematic: few of these scripts have even
basic unit tests. That alone is cause for concern.

  etc/maas/templates/commissioning-user-data/snippets/maas_enlist.sh
  etc/maas/templates/commissioning-user-data/user_data.template
  etc/maas/templates/commissioning-user-data/user_data_disk_erasing.template
  etc/maas/templates/commissioning-user-data/user_data_poweroff.template
  etc/maas/templates/power/*.template