[dovecot/core] ecfca4: auth: test-lua - zero out auth settings in test

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/dovecot/core
  Commit: ecfca41e9d998a0f21ce7a4bce1dc78c58c3e015
      https://github.com/dovecot/core/commit/ecfca41e9d998a0f21ce7a4bce1dc78c58c3e015
  Author: Aki Tuomi <aki.tuomi at dovecot.fi>
  Date:   2017-11-28 (Tue, 28 Nov 2017)

  Changed paths:
    M src/auth/test-lua.c

  Log Message:
  -----------
  auth: test-lua - zero out auth settings in test

Otherwise valgrind complains