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 #58292
amd64 docker linux
precheck:debian:sid:amd64

00:00:18

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

00:03:16

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

00:03:34

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

00:01:24

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

00:02:33

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

00:02:55

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

00:04:45

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

00:04:47

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

00:04:47

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

00:05:01

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

00:01:08

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

00:01:06

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

00:00:58

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

00:00:59