HotFix for: local variable 'subtitles' referenced before assignment

https://github.com/SiCKRAGETV/SickRage/pull/1796 adds a check for
Exception ServiceError, but doesn't return on the exception. For every
other exception the function is returned from.

Fixes https://github.com/SiCKRAGETV/sickrage-issues/issues/1359