workaround for bug #21797

when the side engine in multiplayer_connect_engine.cpp loads a side,
if the game is a save game, the side is not allowed to have a human
player, and it is listed as "network", then we set it to ai,
assuming that it "should" be a "network_ai" if bug #18829 is ever
fixed
blindfold_enabled => skip_replay enabled, in playmp_controller

this was suggested by Wintermute, as it is hard to see why you
wouldn't want the replays to go fast if you can't see anything.
Merge branch 'master' of https://github.com/wesnoth/wesnoth