If pear installs a package, it replaces all occurrences of data_dir with
the actual dirname. This should not have happened in then shipped
version.

Change-Id: I207fd879d55412f97c93ed1bee25d8283f4f6d6c
Fixes: #34923
Releases: 6.0, 4.7, 4.6
Reviewed-on: http://review.typo3.org/9693
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn