adapt dummy test data to fix indeterministically failing test

https://travis-ci.org/fphammerle/freesurfer-volume-reader/jobs/527815463

tests/ashs_test.py

@@ -75,7 +75,7 @@ def test_hippocampal_subfields_volume_file_read_volumes_mm3_not_found():
     (os.path.join(SUBJECTS_DIR, 'alice', 'final', 'alice_left_heur_volumes.txt'),
      pandas.DataFrame({
          'subfield': ['CA1', 'CA2+3', 'DG', 'ERC', 'PHC', 'PRC', 'SUB'],
-         'volume_mm^3': [679.904, 124.459, 902.237, 679.904, 2346.879, 2346.671, 458.782],
+         'volume_mm^3': [679.904, 124.459, 902.237, 789.012, 2346.879, 2346.671, 458.782],
          'subject': 'alice',
          'hemisphere': 'left',
          'correction': None,

tests/subjects/alice/final/alice_left_heur_volumes.txt

@@ -1,7 +1,7 @@
 alice left CA1 26 679.904
 alice left CA2+3 26 124.459
 alice left DG 25 902.237
-alice left ERC 18 679.904
+alice left ERC 18 789.012
 alice left PHC 16 2346.879
 alice left PRC 26 2346.671
 alice left SUB 26 458.782