fix a typo in usage output

(cherry picked from commit e7c99e42)
14 jobs for fix-typo-v9_12 in 8 minutes and 56 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Precheck
passed precheck:debian:sid:amd64 #58292
amd64 docker linux

00:00:18

 
  Build
passed build:centos:centos6:amd64 #58293
amd64 docker linux

00:03:16

passed build:centos:centos7:amd64 #58294
amd64 docker linux

00:03:34

passed build:debian:sid:amd64 #58295
amd64 docker linux

00:01:24

passed build:debian:sid:i386 #58296
i386 docker linux

00:02:33

 
  Test
passed install:debian:sid:amd64 #58305
amd64 docker linux

00:02:55

passed systemtest:centos:centos6:amd64 #58301
amd64 docker linux

00:04:45

passed systemtest:centos:centos7:amd64 #58302
amd64 docker linux

00:04:47

passed systemtest:debian:sid:amd64 #58303
amd64 docker linux

00:04:47

passed systemtest:debian:sid:i386 #58304
i386 docker linux

00:05:01

passed unittest:centos:centos6:amd64 #58297
linux amd64 docker

00:01:08

passed unittest:centos:centos7:amd64 #58298
amd64 docker linux

00:01:06

passed unittest:debian:sid:amd64 #58299
amd64 docker linux

00:00:58

passed unittest:debian:sid:i386 #58300
i386 docker linux

00:00:59