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.

This lifts batman-adv and alfred to version 2016.4.

Introduce new fixes:

 * Avoid nullptr dereference in bla after vlan_insert_tag
 * Avoid nullptr dereference in dat after vlan_insert_tag
 * Avoid tt_req_node list put for unhashed entry
 * Fix orig_node_vlan leak on orig_node_release
 * Fix non-atomic bla_claim::backbone_gw access
 * Fix reference leak in batadv_find_router
 * Free last_bonding_candidate on release of orig_node

Also replace the gluon version of the speedyjoin patch with the one already
included in openwrt-routing.

Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>