Improve ncd status logging

Fixes #12.

In addition, restore the original formatting of ncd status line in `/var/log/ncm-cdispd` to avoid breaking existing parser for this file (I know that line is parsed to raise attention when a component failed).

Still work in progress, would like to add the list of failed components as described in #12.
I think it should not happen... but if there is an empty message, the file with be empty and $fh will be an empty string so that should not cause an error. the fact that there is no message after ':' will mean the message was empty. Is it work building a different log message when the message is empty (making less clear it was empty)? If you think that yes, I'll happily do it!