Undo sub_env for pip install, it was a terrible idea (#467)

* 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>

* be more agressive with blacklisting

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

* sub_env was a terrible idea

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

* changelog update

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

CHANGELOG.md

 # Python Buildpack Changelog
 
+# 115
+
+Revert a pull request.
+
+- No longer using `sub_env` for `pip install` step.
+
 # 114
 
 - Bugfixes.
@@ -8,7 +14,7 @@ Blacklisting `PYTHONHOME` and `PYTHONPATH` for older apps. Upgrades to nltk supp
 
 # 113
 
-- Updates to Pipenv support.
+Updates to Pipenv support.
 
 # 112
 

bin/steps/pip-install

@@ -6,10 +6,8 @@ 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
+    /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