Revert "smbd: add an effective connection_struct->user_ev_ctx that holds the event...

Revert "smbd: add an effective connection_struct->user_ev_ctx that holds the event context used for the current user"

This reverts commit f2df8be16be9dccd3d10ec060f1efbe5007a28c6.

See the discussion in

https://lists.samba.org/archive/samba-technical/2018-December/131731.html

for the reasoning behind this revert.

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>