Bug fix round-up for SF#2885593, SF#2924219 and SF#2946094.

Bug fix round-up for SF#2885593, SF#2924219 and SF#2946094.

Thanks to ZeRoFiGhter for finding and analyzing these.

src/chanserv.c (cmd_move): Scan all users' presence in the new channel.
  (merge_users): Use the newer "seen" time when merging.  Scan source
    users' presence in the new channel.
  (cmd_mdel_user): "actor" already considers whether the user is helping,
    so use that information.
  (handle_join): Allow queuing dynlimit updates during burst.
src/mod-helpserv.c (handle_join): Fix request list indexing.
src/proto-p10.c (irc_kill): Don't insert self in the kill path; our
    uplink does that (at least for ircu2.10.12.x).