Update README.rst format to match expectations
Update README.rst format to match expectations

The release notes script expects to be able to find the link
to the bug tracker in the README.rst, so update the format
to match what is expected by that script and used by the other
projects.

Change-Id: Ifd20c23eb7ba69090cda2e5ecf206f15e81a8254

apporc/oslo.messaging,ozamiatin/oslo.messaging,zhurongze/oslo.messaging,zhurongze/oslo.messaging,isyippee/oslo.messaging,magic0704/oslo.messaging,dukhlov/oslo.messaging,stevei101/oslo.messaging,stevei101/oslo.messaging,dukhlov/oslo.messaging,dims/oslo.messaging,ozamiatin/oslo.messaging,dims/oslo.messaging,hkumarmk/oslo.messaging,hkumarmk/oslo.messaging,isyippee/oslo.messaging,magic0704/oslo.messaging,apporc/oslo.messaging