Clean up EP-Filter after delete project/endpoint

For endpoint_filter extension we should remove all the endpoint
to project associations when we delete the associated endpoint
or project. Otherwise list_endpoints_for_project and
list_projects_for_endpoint API will return 404 response if the
associated endpoint or project has been deleted. Also, there will
be a lot of dirty data remaining in the database.

Change-Id: I48e9100a8fa92d10b7ffe5f89bfb8ba9cf78a0e7
Closes-Bug: #1305537
Merge "Clean up EP-Filter after delete project/endpoint"