Fixing Python 3.9 build to actually use 3.9

Author: henryiii

.travis.yml

@@ -134,11 +134,7 @@ matrix:
           - python3.9-dev
           - python3.9-venv
     # Currently there are no numpy/scipy wheels available for python3.9
-    # TODO: remove next before_install, install and script clause when the wheels become available
-    before_install:
-      - pyenv global $(pyenv whence 2to3)  # activate all python versions
-      - PY_CMD=python3
-      - $PY_CMD -m pip install --user --upgrade pip wheel setuptools
+    # TODO: remove next install and script clause when the wheels become available
     install:
       - $PY_CMD -m pip install --user --upgrade pytest
     script: