Blacklist for old apps (#466)

* fixed the bug for pypy-5.8.0

* update changelog

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>

* blacklist for old apps

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>

* only blacklist pythonhome/path

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>

* updated changelog

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>

CHANGELOG.md

 # Python Buildpack Changelog
 
+# 114
+
+- Bugfixes.
+
+Blacklisting `PYTHONHOME` and `PYTHONPATH` for older apps. Upgrades to nltk support.
+
 # 113
 
 - Updates to Pipenv support.

bin/steps/pip-install

@@ -6,6 +6,9 @@ if [ ! "$SKIP_PIP_INSTALL" ]; then
     puts-step "Installing requirements with pip"
 
     set +e
+    BLACKLIST='PYTHONHOME|PYTHONPATH'
+    export BLACKLIST
+
     sub_env /app/.heroku/python/bin/pip install -r "$BUILD_DIR/requirements.txt" --exists-action=w --src=/app/.heroku/src --disable-pip-version-check --no-cache-dir 2>&1 | tee "$WARNINGS_LOG" | cleanup | indent
     PIP_STATUS="${PIPESTATUS[0]}"
     set -e