:cry::gun: use an empty hash for magical speed.

For some reason, if the hash is empty, we choose "optimized" routes.  I
am not sure how or why optimized routes differ from regular routes.
But, if we make sure the hash is empty, we get a nice speed improvement.
Revert "reduce conditionals in url_for"

This reverts commit 9df60693d77813b362fb528fc62381ac8f1eec12.