remove unneeded requirements.txt

.travis.yml

@@ -10,7 +10,7 b' before_install:'
     - git clone --quiet --depth 1 https://github.com/minrk/travis-wheels travis-wheels
     - 'if [[ $GROUP != js* ]]; then COVERAGE=""; fi'
 install:
-    - pip install -f travis-wheels/wheelhouse -r requirements.txt -e file://$PWD#egg=ipython[test]
+    - pip install -f travis-wheels/wheelhouse -e file://$PWD#egg=ipython[test]
     - pip install codecov
 script:
     - cd /tmp && iptest --coverage xml && cd -