Initialize blockstore after loading pool configuration to pre-shard the DB correctly on start

src/blockstore/blockstore_impl.h

@@ -142,7 +142,6 @@ public:
     int metadata_buf_size;
     blockstore_init_meta* metadata_init_reader;
 
-    void init();
     void check_wait(blockstore_op_t *op);
     void init_op(blockstore_op_t *op);
 
@@ -190,6 +189,8 @@ public:
     void parse_config(blockstore_config_t & config);
     void parse_config(blockstore_config_t & config, bool init);
 
+    void reshard(pool_id_t pool, uint32_t pg_count, uint32_t pg_stripe_size);
+
     // Event loop
     void loop();