Corrects service URLs from "%s/%s/" to "%s/%s"

Reasons:
- "%s/%s/" adds extra / making it "//" whenever it goes to the resources
  like nova or heat or cinder.
- Though it was working fine for nova and cinder, but following recent
  changes on heat/heat-client this is giving an error:
  "The resource could not be found.".

Changes:
- Updates the URLs from "%s/%s/" to "%s/%s".

Change-Id: I95b2601c7eaf577eb13590cbb74255ecbd5b9f1d
Closes-Bug: #1271126
Merge "Corrects service URLs from "%s/%s/" to "%s/%s""