Line numbers in reek >= 1.3.4 are shown by default

`reek -n` supresses line numbering on reek versions of 1.3.4 and above,
causing the location list for smells remain empty.

Commit in reek repository that breaks the vim-reek https://github.com/troessner/reek/commit/a4fb58e43651dfb618ffa6a3eb8553d23c574668