[#34] bootstrap: Remove no longer used SpreadMap

After removing State service from the public API, SpreadMap message became
redundant, so it is deleted.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

bootstrap/types.proto

@@ -10,13 +10,6 @@ option (gogoproto.stable_marshaler_all) = true;
 option (gogoproto.stringer_all) =  false;
 option (gogoproto.goproto_stringer_all) = false;
 
-message SpreadMap {
-    // Epoch is current epoch for netmap
-    uint64 Epoch = 1;
-    // NetMap is a set of NodeInfos
-    repeated NodeInfo NetMap = 2 [(gogoproto.nullable) = false];
-}
-
 message NodeInfo {
     // Address is a node [multi-address](https://github.com/multiformats/multiaddr)
     string Address          = 1 [(gogoproto.jsontag) = "address"];

proto-docs/bootstrap.md

@@ -7,7 +7,6 @@
 
   - Messages
     - [NodeInfo](#bootstrap.NodeInfo)
-    - [SpreadMap](#bootstrap.SpreadMap)
     
 
 - [Scalar Value Types](#scalar-value-types)
@@ -36,18 +35,6 @@
 | Options | [string](#string) | repeated | Options is set of node optional information, such as storage capacity, node location, price and etc |
 | state | [NodeInfo.State](#bootstrap.NodeInfo.State) |  |  |
 
-
-<a name="bootstrap.SpreadMap"></a>
-
-### Message SpreadMap
-
-
-
-| Field | Type | Label | Description |
-| ----- | ---- | ----- | ----------- |
-| Epoch | [uint64](#uint64) |  | Epoch is current epoch for netmap |
-| NetMap | [NodeInfo](#bootstrap.NodeInfo) | repeated | NetMap is a set of NodeInfos |
-
  <!-- end messages -->