input/CdioParanoia: update offset only after successful seek

If seeking fails, don't leave the class with a wrong offset.

src/input/plugins/CdioParanoiaInputPlugin.cxx

@@ -275,12 +275,13 @@ CdioParanoiaInputStream::Seek(std::unique_lock<Mutex> &,
 
 	/* calculate current LSN */
 	const int32_t lsn_relofs = new_offset / CDIO_CD_FRAMESIZE_RAW;
-	offset = new_offset;
 
 	{
 		const ScopeUnlock unlock(mutex);
 		para.Seek(lsn_from + lsn_relofs);
 	}
+
+	offset = new_offset;
 }
 
 size_t