keystone endpoint URLs for product-images assume swift-proxy

The endpoint URLs for the product-images service assume that swift-proxy is in use with the default URL scheme, specifically it assumes the base url is /v1/AUTH_$(tenant_id)s which is not the case when using ceph-radosgw.

glance-simplestreams-sync/scripts/glance-simplestreams-sync.py:update_product_streams_service() should construct the URL using the actual configured swift endpoint, and interpolate the dynamic $(tenant_id)s part before storing it per revno [42]

    Example swift-proxy url: http://10.48.134.175/swift/AUTH_1e67abac94cc46728136261536f95817/v1/simplestreams/data/
    Example ceph-radosgw url: http://10.48.134.175:80/swift/v1/simplestreams/data/