connections is actually reset after an hour, and also fix (unlikely)
conditions under which the per-hour query and connection limits could be
exceeded. (Bug #8350)


sql/sql_parse.cc:
  Add time_out_user_resource_limits() function to
  reset the user resource limits before they are
  checked, and add locking to check_mqh() because
  not doing so isn't as safe as the old comment
  explaining its absence said it is.