htable: use pkg for temporary hash table slots used for reload

- free the temporary slots after reload, reported in FS#385

(cherry picked from commit 53689b55632c6208e6326f1a5f4b3c45da216f43)
htable: use system malloc for temporary allocation of hash table realod slots

- copes better with large number of slots, without a need to use shm

(cherry picked from commit 13626ccffeaa7654c58576c3d1cc417dea865ca9)
htable: free temporary slots used to reload hash table via rpc command

- use system memory for temporary slots

(cherry picked from commit f35c49085bdcc623ef45aa33a99af3265d3e6eeb)