Fix PYTHONPATH is not set when running collectstatic

bin/steps/collectstatic

@@ -30,6 +30,7 @@ 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=.
     python "$MANAGE_FILE" collectstatic --noinput --traceback 2>&1 | sed '/^Post-processed/d;/^Copying/d;/^$/d' | indent
     COLLECTSTATIC_STATUS="${PIPESTATUS[0]}"