Change runit recipe to systemd for Fedora.

Fedora is not supported anyway, so it will not break any supported
installation.

SystemD is a better default for fedora, as fedore is using SystemD
for a few releases already. No fedora server without SystemD should
still be in production.

Closes #365

files/gitlab-cookbooks/runit/recipes/default.rb

@@ -40,8 +40,7 @@ when "rhel"
     end
   end
 when "fedora"
-  # TODO: platform_version check for old distro without upstart
-  include_recipe "runit::upstart"
+  include_recipe "runit::systemd"
 else
   include_recipe "runit::sysvinit"
 end