[BUGFIX] Disable some Apache modules first to prevent conflicts

recipes/default.rb

@@ -124,6 +124,8 @@ else
 	end
 end
 
+# enable Apache modules (we need to disable php and prefork)
+execute "a2dismod php#{node['ubuntu_base']['php_version']} mpm_prefork"
 %w{expires deflate rewrite headers http2 ssl proxy_fcgi mpm_event}.each do |module_name|
 	execute 'a2enmod ' + module_name
 end