Comment 7 for bug 1689944

Validated snappy discovery on xenial yakkety and zesty based on /etc/os-relase ID=ubuntu-core:

for name in test-xenial test-yakkety test-zesty; do lxc exec $name -- sed -i 's/ID=ubuntu$/ID=ubuntu-core$/' /etc/os-release; echo $name --------; lxc exec $name -- cat /etc/os-release; lxc exec $name -- python3 -c 'from cloudinit import util; print("Snappy?: %s" % util.system_is_snappy())'; done;
test-xenial --------
NAME="Ubuntu"
VERSION="16.04.2 LTS (Xenial Xerus)"
ID=ubuntu-core
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.2 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial
Snappy?: True

test-yakkety --------

NAME="Ubuntu"
VERSION="16.10 (Yakkety Yak)"
ID=ubuntu-core
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.10"
VERSION_ID="16.10"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="http://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=yakkety
UBUNTU_CODENAME=yakkety
Snappy?: True

test-zesty --------
NAME="Ubuntu"
VERSION="17.04 (Zesty Zapus)"
ID=ubuntu-core
ID_LIKE=debian
PRETTY_NAME="Ubuntu 17.04"
VERSION_ID="17.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=zesty
UBUNTU_CODENAME=zesty
Snappy?: True