Merge pull request #3471 from kongslund/master

[Xenserver] Fix Xenserver VDI creation, take two

lib/fog/xenserver/requests/compute/create_vdi.rb

@@ -25,7 +25,7 @@ module Fog
             Fog::Logger.deprecation(
                 'The attribute #__sr is deprecated. Use #SR instead.'
             )
-            config[:SR] = config[:__sr].reference
+            config[:SR] = config[:__sr]
           end
 
           unless config[:name].nil?