Unset memory table entry, not just the temporary pointer to it on shutdown
Unset memory table entry, not just the temporary pointer to it on shutdown

to fix crash with multiple instances of OpenBLAS, #1692
xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS,xianyi/OpenBLAS