Merge branch 'dovecot-sieve' into 'master'

dovecot: Only enable needed sieve extensions

See merge request !257

roles/dovecot/templates/dovecot.conf.j2

@@ -39,6 +39,8 @@ passdb {
 plugin {
 	sieve = ~/.dovecot.sieve
 	sieve_dir = ~/.sieve
+	# fileinto and mailbox is required by the global spam-to-folder.sieve script
+	sieve_extensions = envelope fileinto imap4flags mailbox regex
 	sieve_global_dir = /etc/dovecot/sieve/global/
 	sieve_global_path = /etc/dovecot/sieve/default.sieve
 	sieve_before = /etc/dovecot/sieve/spam-to-folder.sieve