Reorder imports.

Trying to separate:
1. Stuff for handling the swarm of nodes and generic table data replication
2. Stuff for the object store core application: metadata tables and block management
3. Stuff for the S3 API

src/block.rs

@@ -16,6 +16,7 @@ use crate::error::Error;
 use crate::membership::System;
 use crate::rpc_client::*;
 use crate::rpc_server::*;
+
 use crate::server::Garage;
 
 pub const INLINE_THRESHOLD: usize = 3072;