Remove openstack/database-api from list of projects

The Trove database-api docs have been moved out of the
openstack/database-api repository and into the openstack/trove
repository, so we no longer need openstack/database-api.

Change-Id: Icbca1a349d61286ef74e9e55df057d86cd8cbd85
(cherry picked from commit 13f65ba9d29bb6d89ee9d323f72ca0d3f9e00e78)
Merge "Remove openstack/database-api from list of projects" into stable/icehouse