Revert "Update reference to ActionView::Template::Handler since it was removed from rails"
Revert "Update reference to ActionView::Template::Handler since it was removed from rails"

This reverts commit 41be859adf7cbea61d61f23fc140ee6c9740c84b.

This and the previous reverted commit broke compatibility with old Rails
versions, and didn't seem to fix anything anyway (stable, for instance, was
working just fine on new Rails versions).

What's more, Rails compatibility changes belong in stable.

macressler/haml,nazar-pc/haml,macressler/haml,dg1dd1ngs/haml,tangposmarvin/haml,stanhu/haml,keithpitty/haml,keithpitty/haml,amatsuda/haml,dg1dd1ngs/haml,concord-consortium/haml,stanhu/haml,haml/haml,haml/haml,haml/haml,tangposmarvin/haml,uniba/hamldoc_ja,nazar-pc/haml,haml/haml,sideci-sample/sideci-sample-haml