default to user python path for collectstatic runs (#655)

* default to user python path for collectstatic runs

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

* bugfixes

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

* fix

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

CHANGELOG.md

 # Python Buildpack Changelog
 
+# 126
+
+Bugfixes.
+
 # 125
 
 Bugfixes.

bin/steps/collectstatic

@@ -30,7 +30,8 @@ if [ ! "$DISABLE_COLLECTSTATIC" ] && [ -f "$MANAGE_FILE" ] && [ "$DJANGO_INSTALL
     puts-step "$ python $MANAGE_FILE collectstatic --noinput"
 
     # Run collectstatic, cleanup some of the noisy output.
-    export PYTHONPATH=.
+    PYTHONPATH=${PYTHONPATH:-.}
+    export PYTHONPATH
     python "$MANAGE_FILE" collectstatic --noinput --traceback 2>&1 | sed '/^Post-processed/d;/^Copying/d;/^$/d' | indent
     COLLECTSTATIC_STATUS="${PIPESTATUS[0]}"