Fix build on scaled gears and Jenkins builder

Convert symlinks in app-root/data to relative paths, so the gear data
can be copied over to some other gear without loosing it's functionality.

https://trello.com/c/HOKvYxdJ/224-3-allow-php-pear-to-work-with-jenkins
Merge pull request #7 from VojtechVitek/pear_jenkins

Fix build on scaled gears and Jenkins builder