multipath: block FC rport on checker timeout

A command timeout indicates a loss of connection to the target,
which hasn't been detected via normal means.
So whenever we encounter a command timeout from the checker we
should be setting the FC rport to 'Blocked' to trigger the
normal fast_io_fail / dev_loss_tmo mechanism.

References: bnc#787438

Signed-off-by: Hannes Reinecke <hare@suse.de>