Update to 2.2.12.

Security: Fix possible single byte overflow in mailbox handling code.
Security: Fix possible single byte overflows in the imapd annotate

		extension.

Security: Fix stack buffer overflows in fetchnews (exploitable by

		peer news server), backend (exploitable by admin), and in
		imapd (exploitable by users though only on platforms where
		a filename may be larger than a mailbox name).