checkupdates: don't auto update to older versions
checkupdates: don't auto update to older versions

If for whatever reason the update check results in an older version that we
didn't package, don't "update" to that version if we already packaged newer
versions.

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