buildserver: test build of Checkey and old F-Droid
buildserver: test build of Checkey and old F-Droid

The buildserver should still be able to build old versions of apps, and
Checkey is a verified, reproducible build.

f-droid/fdroid-server,f-droid/fdroid-server,f-droid/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver,f-droid/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver,f-droid/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroid-server,f-droid/fdroidserver,f-droid/fdroidserver