dummy-ups: provide better diagnostics to syslog as well as console

[clepple]

http://news.gmane.org/find-root.php?message_id=54A5C2AE.3080601%40utoronto.ca

If dummy-ups is started via upsdrvctl or other startup scripts, the output of upsdebugx() is not typically logged. Configuration errors are therefore not visible in syslog. Recommend the use of upslogx() instead.

If the 3rd-generation dummy-ups referenced in issue #94 is rewritten from scratch, this should also be taken into consideration.