[Dovecot] v1.2.16 released

http://dovecot.org/releases/1.2/dovecot-1.2.16.tar.gz http://dovecot.org/releases/1.2/dovecot-1.2.16.tar.gz.sig

Just some small fixes.

- imap: Fixed SELECT QRESYNC not to crash on mailbox close if a lot
  of changes were being sent.
- pop3: Fixed a potential hang
- mbox: Creating new mailboxes should base permissions on mail root
  dir, not always use 0600.
- auth: Disable auth caching entirely for master users.