fix casecompare return type for ninfo, tkey, txt

(cherry picked from commit 3ba1d1e4)
7 jobs for 343-casecompare-of-ninfo-tkey-txt-have-wrong-return-type-v9_11 in 6 minutes and 42 seconds (queued for 5 seconds)
Status Job ID Name Coverage
  Precheck
passed #19809
amd64 docker linux
precheck:debian:sid:amd64

00:00:12

 
  Build
passed #19810
amd64 docker linux
build:debian:sid:amd64

00:01:53

passed #19811
i386 docker linux
build:debian:sid:i386

00:01:58

 
  Test
passed #19814
amd64 docker linux
systemtest:debian:sid:amd64

00:04:22

passed #19815
i386 docker linux
systemtest:debian:sid:i386

00:04:30

passed #19812
amd64 docker linux
unittest:debian:sid:amd64

00:00:58

passed #19813
i386 docker linux
unittest:debian:sid:i386

00:00:51