Fix leaf bots being able to initiate userfile transfer to hubs
Only accept share lines from the bot sending the userfile
Fix non-hubs being able to update other bots
Merge branch 'streaming-userfile-aggressiveness' into next

* streaming-userfile-aggressiveness:
  Fix non-hubs being able to update other bots
  Only accept share lines from the bot sending the userfile
  Fix leaf bots being able to initiate userfile transfer to hubs

Conflicts:
	doc/UPDATES