source-repositories does not respect the "Depends-On" notation

[Mathieu Mitchell]

Currently, source-repositories will not honor the "Depends-on" notation. This is because it directly does a git clone of specified repositories. This breaks changes that depend on other in-flight changes, such as [0].

source-repositories should use zuul-cloner where possible, and otherwise fallback to directly use git. This is what other projects that pull dependencies via Git have done, such as puppet modules [1].

[0] https://review.openstack.org/#/c/360547/1/
[1] https://github.com/openstack-infra/puppet-mysql_backup/blob/ec079e793bdc06707833f59c15e8be742b6393ed/spec/spec_helper_acceptance.rb#L34

[Mathieu Mitchell (mat128)]

source-repositories should not pull from zuul-cloner directly. Something external (job config *OR* test harness, yet TBD) should use zuul-cloner and provide the right environment variables for source-repositories to use the correct repository.

[Gregory Haynes (greghaynes)]

I dont think there is a patch up to fix this in dib

[Mathieu Mitchell (mat128)]

I cant recall what the exact solution was, but the code/discussion is at https://review.openstack.org/#/c/363013/