keep the pivate key, required for retries

app/models/user.rb

@@ -508,6 +508,6 @@ class User < ActiveRecord::Base
 
   private
   def clearable_fields
-    self.attributes.keys - ["id", "username", "encrypted_password", "created_at", "updated_at", "locked_at"]
+    self.attributes.keys - ["id", "username", "encrypted_password", "created_at", "updated_at", "locked_at", "serialized_private_key"]
   end
 end

spec/models/user_spec.rb

@@ -1051,7 +1051,6 @@ describe User do
       it 'returns the clearable fields' do
         user = Factory.create :user
         user.send(:clearable_fields).sort.should == %w{
-          serialized_private_key
           getting_started
           disable_mail
           language