better now. Irssi prints a nice message about it only once and you can
abort it with /RMREJOINS command.
"channel query" -> "channel joined"
channels_join() must not use cmd_return|param_error() commands since we
don't necessarily call it from command handler and signal_stop() could
cause some damage.
git-svn-id: http://svn.irssi.org/repos/irssi/trunk@739 dbcabf3a-b0e7-0310-adc4-f8d773084564
