[Dovecot] 0.99.12 released

One change since -rc1 (the last one below).

- Fix memory leaks in LDAP, MySQL and PGSQL userdb/passdb
- Fix hanging when parsing mails that have over 4096 bytes in one
  line (SMTP servers normally don't allow over 1000 bytes so it
  shouldn't be much of a problem)
- FETCH BODYSTRUCTURE sometimes gave a wrong reply
  (eg. with FETCH (BODYSTRUCTURE RFC822.SIZE) if it wasn't cached)
- Never return more than one INBOX in LIST even if there are such
  files. They don't work anyway and it just confuses clients.
- mbox: Don't allow creating INBOX directory by creating/renaming
  mailboxes under it. They just wouldn't work.
- POP3: Don't return PLAIN in SASL list. We don't support initial SASL
  responses, so it only breaks with most clients that try to use it.
- IMAP and POP3 login processes may have sent each line in two IP
  packets, one with the data and another with CR+LF. Some clients
  didn't work because of this.