fix(rss): fix rss ingest when updated_parsed is `None`
fix(rss): fix rss ingest when updated_parsed is `None`

this was reported by sentry

petrjasek/superdesk-core,marwoodandrew/superdesk-core,ancafarcas/superdesk-core,mdhaman/superdesk-core,hlmnrmr/superdesk-core,petrjasek/superdesk-core,ioanpocol/superdesk-core,mdhaman/superdesk-core,mugurrus/superdesk-core,mugurrus/superdesk-core,petrjasek/superdesk-core,marwoodandrew/superdesk-core,nistormihai/superdesk-core,superdesk/superdesk-core,superdesk/superdesk-core,mdhaman/superdesk-core,superdesk/superdesk-core,ancafarcas/superdesk-core,superdesk/superdesk-core,nistormihai/superdesk-core,ioanpocol/superdesk-core,hlmnrmr/superdesk-core,petrjasek/superdesk-core,ioanpocol/superdesk-core,mugurrus/superdesk-core