Stop creating default user for cloud-init

All relatively modern cloud-inits are capable of creating default user
as well as granting root privileges for them. Currently
cloud-init creates pretty much the same sudoers file.
So running steps under the new DIB_DEBIAN_CLOUD_INIT_HELPER
does not make sense for last couple of Debian releases.

Change-Id: I3cebd318f1f0313bba00ecf639328978d3ad0f32

diskimage_builder/elements/debian/install.d/10-cloud-opinions

@@ -20,20 +20,23 @@ if [ ${DIB_DEBUG_TRACE:-1} -gt 0 ]; then
 fi
 set -eu
 set -o pipefail
+
 case "${DIB_RELEASE}" in
     hamm|slink|potato|woody|sarge|etch|lenny|squeeze|wheezy)
         DIB_DEBIAN_ALT_INIT_PACKAGE=${DIB_DEBIAN_ALT_INIT_PACKAGE:-sysvinit}
+        DIB_DEBIAN_CLOUD_INIT_HELPER=${DIB_DEBIAN_CLOUD_INIT_HELPER:-'true'}
         ;;
     *)
         DIB_DEBIAN_ALT_INIT_PACKAGE=${DIB_DEBIAN_ALT_INIT_PACKAGE:-systemd-sysv}
         ;;
 esac
 
-
-adduser --gecos Debian-cloud-init-user --disabled-password --quiet debian
-install -d -m 0755 -o root -g root /etc/sudoers.d
-echo 'debian ALL=(ALL) NOPASSWD:ALL' > /etc/sudoers.d/debian-cloud-init
-chmod 0440 /etc/sudoers.d/debian-cloud-init
+if [ -n "${DIB_DEBIAN_CLOUD_INIT_HELPER:-}" ]; then
+    adduser --gecos Debian-cloud-init-user --disabled-password --quiet debian
+    install -d -m 0755 -o root -g root /etc/sudoers.d
+    echo 'debian ALL=(ALL) NOPASSWD:ALL' > /etc/sudoers.d/debian-cloud-init
+    chmod 0440 /etc/sudoers.d/debian-cloud-init
+fi
 
 if [ "$DIB_DEBIAN_ALT_INIT_PACKAGE" != "sysvinit" ]; then
     # To avoid a conflict against an essential package, we need to remove sysvinit first

releasenotes/notes/debian_cloud_init-8d91b34b96c621fe.yaml

@@ -0,0 +1,8 @@
+---
+other:
+  - |
+    Added a ``DIB_DEBIAN_CLOUD_INIT_HELPER`` variable that controls whether
+    ``debian`` element will attempt to pre-create required users and sudoers
+    file for the default cloud-init user. This should not be needed for any
+    modern Debian distro.
+