Use Travis-provided pypy3

Author: altendky

.travis.yml

@@ -38,18 +38,6 @@ install:
   - easy_install --version
   - pip --version
   - tox --version
-  - |
-    set -ex
-    if [[ $TRAVIS_PYTHON_VERSION == 'pypy3' ]]; then
-        (cd $HOME
-         wget https://bitbucket.org/pypy/pypy/downloads/pypy3.6-v7.1.1-linux64.tar.bz2
-         tar xf pypy3*.tar.bz2
-         pypy3*/bin/pypy3 -m ensurepip
-         pypy3*/bin/pypy3 -m pip install -U virtualenv)
-        export PATH=$(echo $HOME/pypy3*/bin):$PATH
-        export TOXPYTHON=$(echo $HOME/pypy3*/bin/pypy3)
-    fi
-    set +x starting
   - |
     set -ex
     if [[ $TOXENV == 'check' ]]; then