[dovecot/core] 86448b: mail-log: Add mail_log_cached_only setting.

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: 86448bdb60ed69566bc1093dda824133448ed7a0
      https://github.com/dovecot/core/commit/86448bdb60ed69566bc1093dda824133448ed7a0
  Author: Timo Sirainen <timo.sirainen at dovecot.fi>
  Date:   2017-02-15 (Wed, 15 Feb 2017)

  Changed paths:
    M src/plugins/mail-log/mail-log-plugin.c

  Log Message:
  -----------
  mail-log: Add mail_log_cached_only setting.

If enabled, everything except "save" event will log only the fields that can
be looked up from cache. This improves performance if some of the fields
aren't cached and it's not a strict requirement to log them.