[ngrams] fix for first commit after import

This is similar to

purescript-gargantext#594

and

!205/

but for JSON import.
4 jobs for 622-dev-fix-for-first-commit-after-import in 113 minutes and 54 seconds (queued for 6 seconds)
latest
Status Job ID Name Coverage
  Stack
passed #10856
stack

00:07:10

 
  Cabal
passed #10857
cabal

00:47:08

 
  Bench
passed #10858
bench

00:31:42

 
  Test
failed #10859
test

00:27:53

 
Name Stage Failure
failed
test Test
Test suite garg-test-hspec: PASS
Test suite logged to:
/builds/gargantext/haskell-gargantext/dist-newstyle/build/x86_64-linux/ghc-8.10.7/gargantext-0.0.6.9.9.9.4.4/t/garg-test-hspec/test/gargantext-0.0.6.9.9.9.4.4-garg-test-hspec.log
1 of 1 test suites (1 of 1 test cases) passed.
Error: cabal: Tests failed for test:garg-test-tasty from
gargantext-0.0.6.9.9.9.4.4.

Cleaning up file based variables
ERROR: Job failed: exit code 1