Query quantum once for instance's security groups

This patch adds the method get_instance_security_group_bindings()
which returns all the instance_id's and security groups for a given
tenant. This method is then used to avoid querying quantum for it's
security groups when using GET /v2/<project_id>/servers/detail.

Fixes bug 1161518

Change-Id: Ia28d5573c264f0316ab9fb257ca8e7ae35679883
Merge "Query quantum once for instance's security groups"