Remove unnecessary DB call to find EC2 AZs.

Update get_availability_zone_by_host, so it doesn't need a list of services,
and remove unneeded service_get_all_by_host calls. This removes N DB calls in
the EC2 api when doing a DescribeInstances, where N is number if instances
that are being described.

Partially fix bug 1157437

Change-Id: I0050ba736828faad94549bc6e55f4ca1d05dcbe7
Include Co-authored-by entries in AUTHORS

Import latest openstack.common.setup from oslo-incubator, which includes
the fix to include Co-authored-by entries in AUTHORS.

Fixes bug 1158319

Change-Id: I4f0ba09816730d10869c4ca639e2930d266eac8f
Merge "Include Co-authored-by entries in AUTHORS"
Merge "Remove unnecessary DB call to find EC2 AZs."
Imported Translations from Transifex

Change-Id: I8e4e8c28066e586f7c3246f773d91538018b8aef