travis: Simplify package installation

.travis.yml

@@ -9,10 +9,7 @@ if: (type = push AND branch IN (master)) OR (type = pull_request)
 cache: pip
 before_install:
   - export PIP_USE_MIRRORS=true
-  - pip install -U pip setuptools pytest mock # https://github.com/travis-ci/travis-ci/issues/4873
-  - pip install coveralls
-  - git config --global user.name 'travis-ci'
-  - git config --global user.email 'travis@nowhere.edu'
+  - pip install pytest-cov
 install:
   - pip install -e .
 script: coverage run --source=unihan_etl setup.py test