Fix building of tarball

Author: mdboom

Diff for: .travis.yml

@@ -35,7 +35,6 @@ script:
   - python ../matplotlib/tests.py -sv --processes=8 --process-timeout=300
 
 after_failure:
-  - cd ../matplotlib
   - tar cjf result_images.tar.bz2 result_images
   - travis-artifacts upload --path result_images.tar.bz2
   - echo https://s3.amazonaws.com/matplotlib-test-results/artifacts/${TRAVIS_BUILD_NUMBER}/${TRAVIS_JOB_NUMBER}/result_images.tar.bz2