Groups joined with auto_join are not fully initialized

[Thaodan]

If a group is joined with auto_join for example on Bitlbee the channel group isn't fully initialized.
This results in the group channels title/topic being chat-< chat id> instead of the groups name as expected, another effect is that
messages that are send from the user are not send.

Bitlbee/libpurple will say when trying to do so:

bitlbee[2513047]: purple_conversation_get_chat_data: assertion 'conv != NULL' failed
bitlbee[2513047]: purple_conv_chat_send_with_flags: assertion 'chat != NULL' failed

After someone from another client (e.g. also the user it self) did send a message the group channel is fully initialized,
the title is the correct group name and send messages reach the group.