fixed error occuring with last commit, that "test passed" was printed
even though the test failed and output of the corresponding vtu file
paths was suppressed

reviewed by Beatrix



git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@14421 2fb0f335-1f38-0410-981e-8018bf24f1b0