[ngrams] fix postag_algo (#169)

We had CoreNLP hardcoded, however with Spacy this resulted in
selectLems returning no entries, because the algo_id from DB didn't
match. Hence no singulars grouping.
4 jobs for 169-dev-singulars-plurals in 107 minutes and 1 second (queued for 4 minutes and 58 seconds)
Status Job ID Name Coverage
  Cabal
passed #12052
cabal

00:51:57

 
  Stack
passed #12053
stack

00:02:24

 
  Bench
manual #12054
allowed to fail manual
bench
 
  Test
passed #12055
test

00:52:39