Use of a common logging directory

HTTP access log, for example, is customized under a separate stanza from the logging stanza in the server.xml.  As a default, the http access log gets written to the root of the server directory.  A user deploying a server package to CF would have to customize the configuration in order to use the common path as the other log files.  This refactor is to allow for a user to use the runtime variable application.log.dir instead of determining the hard coded path.