Do better cleaning in key_destroy() for VIMAGE case.
SPDB was cleaned using TAILQ_CONCAT() instead of calling key_unlink()
for each SP, thus we need to properly clean lists in each bucket of
V_sphashtbl to avoid panic in hashdestroy() when INVARIANTS is enabled.
Do the same for V_acqaddrhashtbl and V_acqseqhashtbl.
When we are called in DEFAULT_VNET, destroy also all global locks and
drain key_timer callout.
Reported by: kp
Tested by: kp
MFC after: 1 week