Added back setting of 'some_tables_deleted' to not cause deadlocks in mysql_lock_table()


BitKeeper/etc/ignore:
  added tests/bug25714
sql/lock.cc:
  Added comment
sql/log.cc:
  Don't save & restore time fields from thd when it's not needed.
  Fix that we properly detect if open table failed
sql/sql_base.cc:
  Added back setting of 'some_tables_deleted' to not cause deadlocks in
  mysql_lock_table()