[patch] unregister sr_sensors_refresh() after deleting last sensor

Hi, while playing around with softraid, I noticed that it lazily registers the sensor refresh task when the first volume is created, but it never removes it. The attached patch cleans it up when the last sensor is deleted. Having the one task linger around doing nothing every 10s is obviously

Re: Improve fw_update(9) output on errors somewhat

Here's the next iteration. I'll probably commit it later this weekend unless someone finds issues with it. Here we trap errors from `ftp` unless we're using the verbose modes with progress bars. We then parse those to guess whether we might be able to find a different firmware (currently only