Log Message:
Update mail/dovecot2 to v2.3.5.

From the upstream release-note:

NEWS:

+ Lua push notification driver: mail keywords and flags are provided
in MessageNew and MessageAppend events.
+ submission: Implement support for plugins.
+ auth: When auth_policy_log_only=yes, only log what the policy server
response would do without actually doing it.
+ auth: Always log policy server decisions with auth_verbose=yes
- v2.3.[34]: doveadm log errors: Output was missing user/session
- lda: Debug log lines could have shown slightly corrupted
- login proxy: Login processes may have crashed in various ways when
login_proxy_max_disconnect_delay was set.
- imap: Fix crash with Maildir+zlib if client disconnects during APPEND
- lmtp proxy: Fix potential assert-crash
- lmtp/submission: Fix crash when SMTP client transaction times out
- submission: Split large XCLIENT commands to 512 bytes per command,
so Postfix accepts them.
- submission: Fix crash when client sends invalid BURL command
- submission: relay backend: VRFY command: Avoid forwarding 500 and
502 replies back to client.
- lib-http: Fix potential assert-crash when DNS lookup fails
- lib-fts: Fix search query generation when one language ignores a
token (e.g. via stopwords).