The log "removing pending replacing node" is printed whenever a node
jumps to normal status including a normal restart. For example, on
node1, we saw the following when node2 restarts.
[shard 0] storage_service - Node 127.0.0.2 state jump to normal
[shard 0] storage_service - Remove node 127.0.0.2 from pending replacing endpoint
This is confusing since no node is really being replaced.
To fix, log only if a node is really removed from the pending replacing
nodes.
In addition, since do_remove_node will call del_replacing_endpoint,
there is no need to call del_replacing_endpoint again in
storage_service::handle_state_normal after do_remove_node.
Fixes#6936
bdaf904864