Horizon login failing due to incorrect endpoint

Update data mappings so that horizon uses the public keystone endpoint
(port 5000) instead of the internal keystone endpoint (35357) to allow
users to log in.

Change-Id: I7d6298fbffb81e8f8929a2f2e74b6ef9f4c59b6a
Closes-Bug: #1322282
Merge "Horizon login failing due to incorrect endpoint"