don't hardcode cedar-14

bin/compile

@@ -178,7 +178,7 @@ if [ ! "$SKIP_INSTALL" ]; then
     # Prepare destination directory.
     mkdir -p .heroku/python
 
-    curl http://lang-python.s3.amazonaws.com/cedar-14/runtimes/$PYTHON_VERSION.tar.gz -s | tar zxv -C .heroku/python &> /dev/null
+    curl http://lang-python.s3.amazonaws.com/$STACK/runtimes/$PYTHON_VERSION.tar.gz -s | tar zxv -C .heroku/python &> /dev/null
     if [[ $? != 0 ]] ; then
       puts-warn "Requested runtime ($PYTHON_VERSION) is not available on the $STACK stack."
       puts-warn "Aborting.  More info: https://devcenter.heroku.com/articles/python-support"