Item12942: Log using servertime

This makes the Foswiki logger consisitent with Syslog and Apache logs.
It also ensures that the log rollover happens at midnight at the server
time.  GMT "midnight" might be an inconvient time.

git-svn-id: http://svn.foswiki.org/trunk/core@17766 0b4bb1d4-4e5a-0410-9cc4-b2b747904278