utils: silence a coverity warning

There's no real change, as the function is documented to possibly
return only zero or one in this case.
5 jobs for <span class="ref-name">coverity-fread</span> in 2 minutes and 1 second
Status Job ID Name Coverage
  Build
canceled #72979
docker linux amd64
build:linux:amd64

passed #32462
docker linux amd64
build:linux:amd64

00:00:36

 
  Test
passed #32464
docker linux amd64
deckard:linux:amd64

00:00:31

passed #32465
docker linux amd64
respdiff:linux:amd64

00:02:01

passed #32463
docker linux amd64
test:linux:amd64

00:00:20