Fix help strings
Fix help strings

Use sentence style capitalization on help strings.

Change-Id: Ib3a8393eb0f3244d2ee431e71d3632195903b708

zhurongze/oslo.messaging,hkumarmk/oslo.messaging,redhat-openstack/oslo.messaging,apporc/oslo.messaging,JioCloud/oslo.messaging,zhurongze/oslo.messaging,viggates/oslo.messaging,redhat-openstack/oslo.messaging,ozamiatin/oslo.messaging,eayunstack/oslo.messaging,isyippee/oslo.messaging,hkumarmk/oslo.messaging,dukhlov/oslo.messaging,dims/oslo.messaging,magic0704/oslo.messaging,apporc/oslo.messaging,ozamiatin/oslo.messaging,isyippee/oslo.messaging,dukhlov/oslo.messaging,stevei101/oslo.messaging,stevei101/oslo.messaging,magic0704/oslo.messaging,dims/oslo.messaging