innobase_shutdown_for_mysql(): Do very fast shutdown
  only if srv_fast_shutdown==2, not if srv_fast_shutdown!=0
  (Bug #9673)


innobase/srv/srv0start.c:
  innobase_shutdown_for_mysql(): Do very fast shutdown
  only if srv_fast_shutdown==2, not if srv_fast_shutdown!=0
  (Bug #9673)