manage_etc_hosts: yes writes wrong hostname with custom hostname

I use a cloud config like this:

#cloud-config
hostname: adt
manage_etc_hosts: true

Then I start an instance with "nova boot [...] adt-wily-amd64-puppet-test". This correctly creates /etc/hostname, but /etc/hosts is wrong:

$ cat /etc/hostname
adt

$ cat /etc/hosts
# Your system has configured 'manage_etc_hosts' as True.
# As a result, if you wish for changes to this file to persist
# then you will need to either
# a.) make changes to the master file in /etc/cloud/templates/hosts.tmpl
# b.) change or remove the value of 'manage_etc_hosts' in
# /etc/cloud/cloud.cfg or cloud-config from user-data
#
127.0.1.1 adt-wily-amd64-puppet-test.novalocal adt
[...]

This results in the fully qualified host name not being resolvable, which breaks e. g. puppet:

$ ping adt.novalocal
ping: unknown host adt.novalocal

$ sudo puppet agent --test --detailed-exitcodes
Warning: Setting templatedir is deprecated. See http://links.puppetlabs.com/env-settings-deprecations
   (at /usr/lib/ruby/vendor_ruby/puppet/settings.rb:1134:in `issue_deprecation_warning')
Warning: Unable to fetch my node definition, but the agent run will continue:
Warning: getaddrinfo: Name or service not known
Info: Retrieving pluginfacts
Error: /File[/var/lib/puppet/facts.d]: Failed to generate additional resources using 'eval_generate': getaddrinfo: Name or service not known
Error: /File[/var/lib/puppet/facts.d]: Could not evaluate: Could not retrieve file metadata for puppet://adt.novalocal/pluginfacts: getaddrinfo: Name or service not known
Wrapped exception:
getaddrinfo: Name or service not known
Info: Retrieving plugin
Error: /File[/var/lib/puppet/lib]: Failed to generate additional resources using 'eval_generate': getaddrinfo: Name or service not known
Error: /File[/var/lib/puppet/lib]: Could not evaluate: Could not retrieve file metadata for puppet://adt.novalocal/plugins: getaddrinfo: Name or service not known
Wrapped exception:
getaddrinfo: Name or service not known
Error: Could not retrieve catalog from remote server: getaddrinfo: Name or service not known
Warning: Not using cache on failed catalog
Error: Could not retrieve catalog; skipping run
Error: Could not send report: getaddrinfo: Name or service not known