Update hotplug. Add qle_get_port_name_list, use it to discover local

Update hotplug.  Add qle_get_port_name_list, use it to discover local
loop ports and other fabric ports that have logged in to us, and check
that we're still logged in to other fabric ports.  Rearrange the update
processing loop so we attach and detach targets last, since we need to get
all the way through before we've identified what's gone missing.  Handle
fabric port login errors a bit more usefully too.