fix error message for collectstatic

bin/steps/django/collectstatic

@@ -13,20 +13,22 @@ indent() {
 python $MANAGE_FILE collectstatic --help &> /dev/null && RUN_COLLECTSTATIC=true
 
 # Don't raise errors if SILENCE_COLLECTSTATIC is set.
-if [ ! "$SILENCE_COLLECTSTATIC" ]; then
-    set -e
-fi
 
 echo "-----> Collecting static files"
+set -e
 
 # Compile assets if collectstatic appears to be kosher.
 if [ "$RUN_COLLECTSTATIC" ]; then
     python $MANAGE_FILE collectstatic --noinput | indent
 
-    [ $? -ne 0 ] && {
+    COLLECTSTATIC=$?
+
+    [ $COLLECTSTATIC -ne 0 ] && [ ! "$SILENCE_COLLECTSTATIC" ] && {
         echo " !     Error running manage.py collectstatic. More info:"
         echo "       http://devcenter.heroku.com/articles/django-assets"
+        exit 1
     }
+
 else
     echo " !     Django collecstatic is not configured. Learn more:"
     echo "       http://devcenter.heroku.com/articles/django-assets"