* src/p11-getslotlist.c (C_GetSlotList): Fix for Firefox.
* src/slots.c (active_sessions): New.
(slot_create_session): Increment ACTIVE_SESSIONS.
(slot_close_session): Decrement ACTIVE_SESSIONS.
(scute_slots_rescan_if_no_sessions): New.
* src/slots.h (scute_slots_rescan_if_no_sessions): New.