[fix] newznab: Fix crash when searching for entries without imdb_id. fix #2543
[fix] newznab: Fix crash when searching for entries without imdb_id. fix #2543

Flexget/Flexget,Flexget/Flexget,crawln45/Flexget,Flexget/Flexget,malkavi/Flexget,crawln45/Flexget,malkavi/Flexget,malkavi/Flexget,Flexget/Flexget,malkavi/Flexget,ianstalk/Flexget,crawln45/Flexget,ianstalk/Flexget,ianstalk/Flexget,crawln45/Flexget