Fix call to super when raising DebugKitBadVersion

In Ruby, `super` implicitly passes a copy of the arguments a method received.
When raising a `DebugKitBadVersion` error, the `initialize` method has a
different signature than `super`, so we must explicitly pass the right
arguments.

Fixes GH-1.

lib/puppet_debugging_kit/plugin_checks.rb

@@ -8,7 +8,7 @@ class DebugKitBadVersion < Vagrant::Errors::VagrantError
       def initialize(plugin, required, actual)
         @error_message = "Outdated debugging kit dependency: #{plugin}\nMinimum required version is: #{required}\nInstalled version is: #{actual}\nTry: vagrant plugin update #{plugin}"
 
-        super
+        super @error_message
       end
 
       def error_message; @error_message; end