[Doc] Fix small typo in cli_reference
[Doc] Fix small typo in cli_reference

Change-Id: Ied595d4b8e08ec8f6cf0ef8b16b543d92650dd91

openstack/rally,gluke77/rally,openstack/rally,eonpatapon/rally,gluke77/rally,vganapath/rally,eayunstack/rally,yeming233/rally,vganapath/rally,eonpatapon/rally,gluke77/rally,vganapath/rally,gluke77/rally,eayunstack/rally,vganapath/rally,openstack/rally,eayunstack/rally,yeming233/rally,openstack/rally