[ENBD] 2.5.46 update

[Peter T. Breuer]

"A month of sundays ago Peter T. Breuer wrote:"
> I don't understand how list_del can immediately be followed by
> !list_empty  !!

Heisenbug.


Replace list_del by list_del_init everywhere.


The kernel doesn't guarantee to leave the entry in a consistent state
after list_del, and they've just started testing for the request's
"queue" (the place it is notionally attached to) being empty elsewhere
in the kernel in the kernel routines. It triggers a BUG call.


Peter