Add option to ignore failed fans

[odenbach]

Hi,

I have a box with some fans in it which are connected to the mainboard instead of the enclosure. The mainboard reports all fans as working properly. tw-cli however reports the fans as failed (as they are not connected). I reported this to the manufacturer and they told me to simply ignore the fan warnings in tw-cli's output.

So this pull request adds a simple plugin option 'ignore-fans=1' which then disables checking of fans (and of the main enclosure status which goes to WARNING if anything seems b0rken).

Thanks,

Christopher
tw-cli.txt

[glensc]

can you add test case for new scenarios?

and add documentation of the option in the plugin file as pod so check_raid users would be aware of the new option.

as no other plugin has documentation in pod, use your imagination