[bugfix] fixe a memory leak revealed by 8c470b13

When finding follows, sentences given to be computed were shared among
different k, however, instead of marking the first that is inserted as
malloced, only k == 0 was marked as such.

Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>
[bugfix] fix a memory leak in a previous commit

Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>