Timeout option takes no effect

[Kaifeng Wang]

The ilo driver used by ironic accept a client_timeout value to control request timeout, but this value is not used in many places, e.g. ribcl.get_product_name, ribcl.get_host_power_status, no timeout provided to the requests lib, the default value is used every time.
When the server is down, it costs quite some time for ironic to know the power failure and put the maintenance mode.