Add LogLevels functionality through the addition of aplog_error().

This change also provides the ability to log errors via syslogd.
Reviewed by:	Dean Gaudet, Jim Jagielski, Ken Coar


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@79061 13f79535-47bb-0310-9956-ffa450edef68