Update "dovecot2" package to version 2.1.11. Changes since 2.1.10:
- lmtp/lda: dovecot.index.cache file is no longer fully mapped to
  memory, allowing mail deliveries to work even if the file is huge.
- auth: userdb passwd lookups are now done by auth worker processes
  instead of auth master process (as it was documented, but
  accidentally didn't work that way).
- lmtp: lmtp_rcpt_check_quota=yes setting checks quota on RCPT TO.
- lmtp: After successful proxying RCPT TO, the next one to a
  nonexistent user gave tempfail error instead of "user not found".
- lmtp proxy: Fixed hanging if remote server was down.
- imap: Fixed crash when SEARCH contained multiple KEYWORD parameters.
- doveadm: Various fixes to handling doveadm-server connections.
- -i <instance name> parameter for Dovecot tools didn't work correctly.
- director was somewhat broken in v2.1.10. This version also includes
  various reliability enhancements.
- auth: passdb imap was broken in v2.1.10.

(tron)