cleanup of design-summit.rst
cleanup of design-summit.rst

removed the time and added the
changed introduce clearly to clear introductions
added “and” and a .
removed - in Rendezvouz

Change-Id: I2230bc0a10de5568c23c19a89fd6139b7f11521c

Nabs007/training-guides,harrisonfeng/training-guides,openstack/training-guides,Nabs007/training-guides,Nabs007/training-guides,harrisonfeng/training-guides,openstack/training-guides,harrisonfeng/training-guides