3rd party CI layout usually has only a few projects defined,
so it's possible that some changes depend on projects
which are unknown to Zuul scheduler.
These items had None as a "item.change.project", which
is not handled in many places, for ex. in reconfiguration.
These cases could be handled by defining these projects in layout
as "foreign" projects: no jobs, no other non-standard attributes.
Changes to those projects are also dropped, unless
they came as dependencies.
Change-Id: I7912197fb86c1a7becb7f43ca36078101f632715
Evgeny Antyshev
0deaaadac7