minor: symlinks to service.properties and log.xml used to refer to full...

minor: symlinks to service.properties and log.xml used to refer to full cannonical path (e.g. /home/openbis/server/jetty-7.1.4/etc/.../). This was causing problems when moving the installation to a different folder. The installation script has been adjusted to point to relative paths now (e.g. ../webapps/openbis/WEB-INF/classes/service.properties)

SVN: 21730