Fix the read-rif utils so that it reads correctly rif coming from prog with no input.

3 jobs for master in 7 minutes and 22 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
passed build #15286

00:04:22

passed build #10122

00:04:10

 
  Test
passed test_opam_test #10123

00:03:00