mysql-test/r/kill-2.result:
  test case for MDEV-6896
mysql-test/t/kill-2-master.opt:
  test case for MDEV-6896
mysql-test/t/kill-2.test:
  test case for MDEV-6896
sql/sql_parse.cc:
  Use host_or_ip instead of host as host may be 0