In some cases, a timer was set to NULL so that we could check if it is
initialized. Use the timer_list field instead, and add a timer_deinit
function that NULLs it.
It then makes sense that timer_del be a no-op (instead of a crasher) on
such a de-initialized timer. It avoids the need to poke at the timerlist
field to check if the timers are initialized.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
cd1bd53a66