[KV]: allow non-thread-safe obj_allocator.
[KV]: allow non-thread-safe obj_allocator.

icoming/FlashGraph,flashxio/FlashX,flashxio/FlashX,zheng-da/FlashX,zheng-da/FlashX,flashxio/FlashX,icoming/FlashX,silky/FlashGraph,icoming/FlashGraph,zheng-da/FlashX,flashxio/FlashX,icoming/FlashX,icoming/FlashGraph,silky/FlashGraph,silky/FlashGraph,icoming/FlashX,icoming/FlashX,silky/FlashGraph,icoming/FlashGraph,silky/FlashGraph,flashxio/FlashX,icoming/FlashX,flashxio/FlashX,icoming/FlashGraph,zheng-da/FlashX,zheng-da/FlashX