fix null reference exception (#3138)
fix null reference exception (#3138)


superdesk/superdesk-client-core,pavlovicnemanja/superdesk-client-core,petrjasek/superdesk-client-core,superdesk/superdesk-client-core,superdesk/superdesk-client-core,superdesk/superdesk-client-core,pavlovicnemanja/superdesk-client-core,superdesk/superdesk-client-core,pavlovicnemanja/superdesk-client-core,petrjasek/superdesk-client-core,petrjasek/superdesk-client-core,petrjasek/superdesk-client-core,pavlovicnemanja/superdesk-client-core,petrjasek/superdesk-client-core,pavlovicnemanja/superdesk-client-core