[dovecot/core] 96de40: Fix link failure against libressl.

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: 96de40971a8915de0840a6ecb00ad94e40c7366a
      https://github.com/dovecot/core/commit/96de40971a8915de0840a6ecb00ad94e40c7366a
  Author: Nick Wallingford <nick at wallingford.cc>
  Date:   2016-12-23 (Fri, 23 Dec 2016)

  Changed paths:
    M src/lib-ssl-iostream/dovecot-openssl-common.c

  Log Message:
  -----------
  Fix link failure against libressl.