By default a given project's label applicable scope is all changes
on all branches of this project and its child projects.
Label's applicable scope can be branch specific via configuration.
E.g. create a label 'Video-Qualify' on parent project and configure
the 'branch' as:
[label "Video-Qualify"]
branch = refs/heads/video-1.0/*
branch = refs/heads/video-1.1/Kino
Then ONLY changes in above branch scope of parent project and child
projects will be affected by 'Video-Qualify'.
Please note the 'branch' is independent from the branch scope related
to access control defined in 'access' parts in 'project.config' file.
That means from the UI a user can always assign permissions for that
label on a branch, but this permission is then ignored if the label
doesn't apply for that branch.
Change-Id: I414e62503b0da4af022abbc9988593ba9ac87916
9b22c3ab2d