Updates batman-adv and alfred to 2017.2 and adds the batman-adv TT-sync
fix.

Fixes #1183

Updates batman-adv and alfred to 2017.1. This also allows us to drop our
last batman-adv patch.

Updates batman-adv to 2017.0.1.

Switch sha512sum to sha256sum to match updated autoupdater.

Also remove our own no_rebroadcast patch, as batman-adv v2016.5 now has a
more sophisticated rebroadcast suppression that should work automatically
in the most relevant cases.