Fixed issue #526 - Import throws error if run a second time.

lib/import/otrs/customer_user.rb

@@ -48,7 +48,7 @@ module Import
 
         # only update roles if different (reduce sql statements)
         if @local_customer.role_ids == customer[:role_ids]
-          user.delete(:role_ids)
+          customer.delete(:role_ids)
         end
 
         log "update User.find_by(login: #{customer[:login]})"

spec/import/otrs/customer_user_spec.rb

@@ -13,7 +13,10 @@ RSpec.describe Import::OTRS::CustomerUser do
   def updates_with(zammad_structure)
     expect_organization_lookup
     expect(import_object).to receive(:find_by).and_return(existing_object)
-    expect(existing_object).to receive(:role_ids).and_return([]).at_least(:once)
+    # we delete the :role_ids from the zammad_structure to make sure that
+    # a) role_ids call returns the initial role_ids
+    # b) and update_attributes gets called without them
+    expect(existing_object).to receive(:role_ids).and_return(zammad_structure.delete(:role_ids)).at_least(:once)
     expect(existing_object).to receive(:update_attributes).with(zammad_structure)
     expect(import_object).not_to receive(:new)
     start_import_test

spec/import/otrs/user_spec.rb

@@ -12,12 +12,18 @@ RSpec.describe Import::OTRS::User do
 
   def updates_with(zammad_structure)
     expect(import_object).to receive(:find_by).and_return(existing_object)
-    expect(existing_object).to receive(:role_ids).and_return([])
+    # we delete the :role_ids from the zammad_structure to make sure that
+    # a) role_ids call returns the initial role_ids
+    # b) and update_attributes gets called without them
+    expect(existing_object).to receive(:role_ids).and_return(zammad_structure.delete(:role_ids))
     expect(existing_object).to receive(:update_attributes).with(zammad_structure)
     expect(import_object).not_to receive(:new)
     start_import_test
   end
 
+  def role_delete_expecations(role_ids)
+  end
+
   def load_user_json(file)
     json_fixture("import/otrs/user/#{file}")
   end