[dovecot/core] e01ebd: imapc: Add imapc_features=fetch-empty-is-expunged

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: e01ebd51ac369430ec81945e3c5317d6d6244138
      https://github.com/dovecot/core/commit/e01ebd51ac369430ec81945e3c5317d6d6244138
  Author: Timo Sirainen <timo.sirainen at dovecot.fi>
  Date:   2017-10-30 (Mon, 30 Oct 2017)

  Changed paths:
    M src/lib-storage/index/imapc/imapc-mail-fetch.c
    M src/lib-storage/index/imapc/imapc-settings.c
    M src/lib-storage/index/imapc/imapc-settings.h

  Log Message:
  -----------
  imapc: Add imapc_features=fetch-empty-is-expunged

When FETCH returns an empty mail, the mail is assumed to be expunged.