update: do not crash if AndroidManifest.xml in APK has invalid date
update: do not crash if AndroidManifest.xml in APK has invalid date

This crash actually blocked a Janus exploit APK from being added to the
repo, but crashing isn't really the appropriate way to do that.

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