Added empty db_check_backend_thread_safe to dbi backend.
Added empty db_check_backend_thread_safe to dbi backend.

rkorzeniewski/bacula,rkorzeniewski/bacula,rkorzeniewski/bacula,rkorzeniewski/bacula,rkorzeniewski/bacula,rkorzeniewski/bacula,rkorzeniewski/bacula,rkorzeniewski/bacula