new static archive_inited variable, so that archive_db_end() will do something only if archive_db_init() was run before
(protection against destroying uninited mutex in the case where mysqld fails early at startup (before archive_db_init() was called)
and then calls archive_db_end() to clean up).


sql/examples/ha_archive.cc:
  new static archive_inited variable, so that archive_db_end() will do something only if archive_db_init() was run before.