systemd: support disabling cloud-init via file or kernel cmdline

This adds a systemd generator for a 'cloud-init.target'.  That target will
be WantedBy multi-user.target in the default case.  If there is a file
/etc/cloud/cloud-init.disabled or the kernel command line contains
'cloud-init=disabled' then cloud-init will not affect boot at all.

There are some packages/debian changes to affect this:
 * postinst, preinst: these are necessary to remove some
   old target files for multi-user.target (LP: #1552999)
 * changes to include these files in the debian source package.
 * rules.in: supports DEB_BUILD_OPTIONS=nocheck to not run check

setup.py: mostly changes to support installing the generator
          but also pep8 fixes along the way

systemd/*: make each of the services 'WantedBy=cloud-init.target'
           rather than being wanted by multi-user.target

1 files changed, 20 insertions, 0 deletions

diff --git a/packages/debian/cloud-init.preinst b/packages/debian/cloud-init.preinst
new file mode 100644
index 00000000..3c2af06d
--- /dev/null
+++ b/packages/debian/cloud-init.preinst
@@ -0,0 +1,20 @@
+#!/bin/sh
+# vi: ts=4 expandtab
+
+cleanup_lp1552999() {
+    local oldver="$1" last_bad_ver="0.7.7~bzr1178"
+    dpkg --compare-versions "$oldver" le "$last_bad_ver" || return 0
+    local hdir="/var/lib/systemd/deb-systemd-helper-enabled"
+    hdir="$hdir/multi-user.target.wants" 
+    local edir="/etc/systemd/system/multi-user.target.wants"
+    rm -f "$hdir/cloud-config.service" "$hdir/cloud-final.service" \
+        "$hdir/cloud-init-local.service" "$hdir/cloud-init.service"
+}
+
+
+if [ "$1" = "upgrade" ]; then
+   oldver="$2"
+   cleanup_lp1552999 "$oldver"
+fi
+
+#DEBHELPER#