[BUGFIX] Remove obsolete prefork package stuff

recipes/default.rb

@@ -130,8 +130,7 @@ else
 	end
 end
 
-# enable Apache modules (we need to disable php and prefork)
-execute "a2dismod php#{node['ubuntu_base']['php_version']} mpm_prefork"
+# enable Apache modules
 %w{expires deflate rewrite headers http2 ssl proxy_fcgi mpm_event}.each do |module_name|
 	execute 'a2enmod ' + module_name
 end