modules/sca: fix hash entry deletion
sca_hash_table_slot_kv_delete_unsafe() uses internally sca_hash_entry
but incorrectly called sca_hash_table_slot_kv_find_unsafe() to
initialize the entry. That function returns the node value, not the
node itself. Use instead sca_hash_table_slot_kv_find_entry_unsafe().
Should fix the crash in FS#366.