[BUGFIX] PHP warning: open_basedir restriction

Change-Id: Ie1dfe4306cad8bdc23864f31a77dac980eac3494
Fixes: #42054
Relates: #35212
Releases: 4.6, 4.7, 6.0
Reviewed-on: http://review.typo3.org/15741
Reviewed-by: Mattias Nilsson
Reviewed-by: Stefan Neufeind
Reviewed-by: Michael Stucki
Tested-by: Michael Stucki