Move ec2authtoken config from paste.ini to conf

Nothing now needs to be configured in paste.ini on launch

This change relates to these committed Heat changes:
https://review.openstack.org/#/c/27382/
https://review.openstack.org/#/c/27382/

Change-Id: Ia29dee8e32cd3d43d1b9200dd94de70e02a54bfc
Install api-paste.ini and policy.json

This is related to this Heat change, and Heat on Devstack will not work
while only one of these changes is applied:
Consolidated api-paste.ini file
https://review.openstack.org/#/c/27384/

Change-Id: Iba02b56173f796de5348289247233c8765f83ac2
Merge "Move ec2authtoken config from paste.ini to conf"
Merge "Install api-paste.ini and policy.json"