remove old code for rails 3x and update haml dependency

Author: Ruslan Korolev

haml-rails.gemspec

@@ -15,7 +15,7 @@ Gem::Specification.new do |s|
   s.rubyforge_project         = "haml-rails"
   s.required_rubygems_version = ">= 1.3.6"
 
-  s.add_dependency "haml",          [">= 3.1", "< 5.0"]
+  s.add_dependency "haml",          [">= 4.0.6", "< 5.0"]
   s.add_dependency "activesupport", [">= 4.0.1"]
   s.add_dependency "actionpack",    [">= 4.0.1"]
   s.add_dependency "railties",      [">= 4.0.1"]

lib/haml-rails.rb

@@ -7,14 +7,9 @@ module Rails
     class Engine < ::Rails::Engine
     end
     class Railtie < ::Rails::Railtie
-      if ::Rails.version.to_s >= "3.1"
-        config.app_generators.template_engine :haml
-      else
-        config.generators.template_engine :haml
-      end
+      config.app_generators.template_engine :haml
 
       config.before_initialize do
-        Haml.init_rails(binding)
         Haml::Template.options[:format] = :html5
       end