In case when enforce_new_defaults is set to True in config, Neutron
shouldn't check context.is_admin flag to check if query should or
shouldn't be scoped to just one tenant as user with PROJECT_ADMIN role
will have is_admin flag set to True but such user shouldn't get e.g.
networks which belongs to other tenants and aren't shared in any way.
So that patch improves neutron_lib.db.utils.model_query_scope_is_project
function so it works in different way in case when enforce_new_defaults
is set to True or False. In case when new defaults should be enforced
only SYSTEM_SCOPE tokens and advanced_services can make queries which
are not scoped to single tenant.
Closes-Bug: #1919386
Change-Id: I7760413a562e5d1a86709fc5e2d0df405a6aed30
d73449dd1c