Fix typo in the code comment
Fix typo in the code comment

Line62- # and than do what you need with this client

"than" is not suitable in the sentence.
"then" is correct.

Change-Id: Ic2b6999d522a0aa797bece452509217cbbf12be0
Closes-Bug: #1490359

yeming233/rally,afaheem88/rally,amit0701/rally,group-policy/rally,paboldin/rally,gluke77/rally,group-policy/rally,redhat-openstack/rally,afaheem88/rally,vganapath/rally,openstack/rally,eonpatapon/rally,paboldin/rally,amit0701/rally,cernops/rally,aplanas/rally,paboldin/rally,openstack/rally,eonpatapon/rally,openstack/rally,gluke77/rally,openstack/rally,redhat-openstack/rally,vganapath/rally,aplanas/rally,eayunstack/rally,amit0701/rally,eayunstack/rally,gluke77/rally,group-policy/rally,gluke77/rally,cernops/rally,vganapath/rally,vganapath/rally,aforalee/RRally,eayunstack/rally,aforalee/RRally,yeming233/rally