* infiniband: Add not connected i40iw0/ports/1 fixtures
* infiniband: Handle issue when iWARP* RDMA modules are not available
This is related to #966, and handle this error,
Jun 07 13:33:24 hostname node_exporter[81888]: time="2018-06-07T13:33:24+02:00" level=error msg="ERROR: infiniband
collector failed after 0.000929s: strconv.ParseUint: parsing \"N/A (no PMA)\": invalid syntax" source="collector.go:132"
Signed-off-by: Mario Trangoni <mjtrangoni@gmail.com>