Prevent database creation on Debian

When Debian install slapd, it configure it by default with a database
that match the hostname unless overriden by a preseed file as we did
before.  This however has consequences on the database created by the
module that prevent it from being restored after being dumped.

Remove this custom database name and request no_configuration from the
preseed file.  This requires us to bootstrap the cn=config database, but
also prevent the package from installing correctly ([709472]).
Workaround this issue with some systemd presets.

Fixes #366

[709472]:https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=709472

manifests/server/config.pp

@@ -50,6 +50,16 @@
         variable => 'SLAPD_SERVICES',
         value    => $slapd_ldap_urls,
       }
+
+      # Debian configuration include database creation. We skip this with
+      # preseeding files so we need to manualy bootstrap cn=config.
+      exec { 'bootstrap cn=config':
+        command => "/usr/sbin/slapadd -n 0 -F ${openldap::server::confdir} -l /usr/share/slapd/slapd.init.ldif",
+        creates => "${openldap::server::confdir}/cn=config.ldif",
+        user    => $openldap::server::owner,
+        group   => $openldap::server::group,
+        require => File[$openldap::server::confdir],
+      }
     }
     'RedHat': {
       if versioncmp($facts['os']['release']['major'], '6') <= 0 {

manifests/server/install.pp

@@ -5,12 +5,27 @@
   contain openldap::utils
 
   if $facts['os']['family'] == 'Debian' {
+    unless defined(File['/etc/systemd/system-preset']) {
+      file { '/etc/systemd/system-preset':
+        ensure => 'directory',
+        owner  => 'root',
+        group  => 'root',
+        mode   => '0755',
+      }
+    }
+    file { '/etc/systemd/system-preset/90-slapd.preset':
+      ensure  => 'file',
+      owner   => 'root',
+      group   => 'root',
+      content => "disable slapd.service\n",
+      before  => Package[$openldap::server::package],
+    }
     file { '/var/cache/debconf/slapd.preseed':
       ensure  => file,
       mode    => '0644',
       owner   => 'root',
       group   => 'root',
-      content => "slapd slapd/domain\tstring\tmy-domain.com\n",
+      content => "slapd slapd/no_configuration\tboolean\ttrue\n",
       before  => Package[$openldap::server::package],
     }
     $responsefile = '/var/cache/debconf/slapd.preseed'