Avoid indexing both direct + indirect translations
Avoid indexing both direct + indirect translations

If a sentence has a translation whose link can be interpreted as both
direct or indirect, depending on the chosen path, then index it as
direct only.

Refs #705.

shashank19gaurav/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,shashank19gaurav/tatoeba2,Tatoeba/tatoeba2,shashank19gaurav/tatoeba2,shashank19gaurav/tatoeba2