Remove leftover protobuf definitions.

proto/message.proto

@@ -1,55 +0,0 @@
-syntax = "proto3";
-
-message MessageProto {
-  oneof payload {
-    BroadcastProto broadcast = 1;
-    AgreementProto agreement = 2;
-  }
-}
-
-message BroadcastProto {
-  oneof payload {
-    ValueProto value = 1;
-    EchoProto echo = 2;
-    ReadyProto ready = 3;
-  }
-}
-
-message ValueProto {
-  ProofProto proof = 1;
-}
-
-message EchoProto {
-  ProofProto proof = 1;
-}
-
-message ReadyProto {
-  bytes root_hash = 1;
-}
-
-message ProofProto {
-  bytes root_hash = 1;
-  LemmaProto lemma = 2;
-  bytes value = 3;
-}
-
-message LemmaProto {
-  bytes node_hash = 1;
-  LemmaProto sub_lemma = 2;
-
-  oneof sibling_hash {
-    bytes left_sibling_hash = 3;
-    bytes right_sibling_hash = 4;
-  }
-}
-
-message AgreementProto {
-  uint32 epoch = 1;
-  oneof payload {
-    bool bval = 2;
-    bool aux = 3;
-    uint32 conf = 4;
-    bool term = 5;
-    bytes coin = 6;
-  }
-}