Mark devel/libgit2-glib as broken, upstream does not support libgit 0.27.0

[mfechner]

Summary

Commit message:
Mark devel/libgit2-glib as broken, upstream does not support libgit 0.27.0

Reviewed by: tz/swills (mentor)
Approved by: tz/swills (mentor), wg (maintainer)
Differential Revision: URL to this revision

Test Plan

All patches are build, you can find all build logs:
https://pkg.fechner.net/jail.html?mastername=111amd64-gitlab

The fresh packages are tested against a new installation using:
https://gitlab.fechner.net/mfechner/Gitlab-vagrant

An old version is updated following the manual:
https://gitlab.fechner.net/mfechner/Gitlab-docu