gitlab-ci: make ubuntu_lts job test of fdroid/fdroidserver PPA
gitlab-ci: make ubuntu_lts job test of fdroid/fdroidserver PPA

Now that androguard is working, there should be no need for a specific aapt
version.  The aapt included in Ubuntu LTS should always work fine when
androguard handles the bulk of the work.

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