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
Removes "RPC not enabled" error message when no backend is needed

When no service needing a RPC backend is activated, no error message
should appear if a RPC backend is not installed. A simple check is
done on the services installation files to see which services need to
initialize a RPC backend at some point; if none of these services
are in ENABLED_SERVICES then the error message is skipped.

Change-Id: I4e47e0c675c74775b4ea53a00848ac1d777f0125
Fixes: bug #1167338
Merge "Removes "RPC not enabled" error message when no backend is needed"
Merge "Move ec2authtoken config from paste.ini to conf"
Merge "Install api-paste.ini and policy.json"