Enable keystone token auth and ec2 auth

This patch enables keystone token auth and ec2 auth. Also it enables
keystone support in tempest.

Also, magnetodb section was added to tempest config.

Change-Id: I3e20ab7c66350cbb4a02c5401c43502b3cbaa461
Implements: blueprint keystone-token-validation
Merge "Enable keystone token auth and ec2 auth"