Uses global roundcube sieve configuration option

The previous behaviour relied on managesieve copying over the
.dovecot.sieve file into the user's directory. I found this to be
particularly fragile. For instance, re-deploying roundcube without
dovecot could overwrite the .dovecot.sieve symlink and break
managesieve.

A better approach is to use the global sieve configuration that
roundcube provides and not mess with dovecot's files directly.

roles/mailserver/tasks/dspam.yml

     - 90-plugin.conf
   notify: restart dovecot
 
-- name: Put sieve rules into each user directory
-  copy: src=dot_dovecot.sieve dest=/decrypted/{{ item.domain }}/{{ item.account }}/.dovecot.sieve owner=vmail group=dovecot
-  with_items: mail_virtual_users
-  notify: restart dovecot

roles/webmail/files/usr_share_roundcube_plugins_managesieve_config.inc.php

 $rcmail_config['managesieve_usetls'] = false;
 
 // default contents of filters script (eg. default spam filter)
-$rcmail_config['managesieve_default'] = '/etc/dovecot/sieve/global';
+$rcmail_config['managesieve_default'] = '/etc/roundcube/global.sieve';
 
 // The name of the script which will be used when there's no user script
-$rcmail_config['managesieve_script_name'] = 'managesieve';
+$rcmail_config['managesieve_script_name'] = 'roundcube';
 
 // Sieve RFC says that we should use UTF-8 endcoding for mailbox names,
 // but some implementations does not covert UTF-8 to modified UTF-7.

roles/webmail/tasks/roundcube.yml

 - name: Configure roundcube's managesieve plugin
   copy: src=usr_share_roundcube_plugins_managesieve_config.inc.php dest=/usr/share/roundcube/plugins/managesieve/config.inc.php group=www-data owner=root mode=640 force=yes
 
+- name: Copy global default sieve rules
+  copy: src=etc_roundcube_global.sieve dest=/etc/roundcube/global.sieve owner=root group=www-data mode=640
+
 - name: Enable roundcube site
   command: a2ensite roundcube creates=/etc/apache2/sites-enabled/roundcube
   notify: restart apache