eth, les: shorten genesis block mismatch error message

eth/peer.go

@@ -280,7 +280,7 @@ func (p *peer) readStatus(network int, status *statusData, genesis common.Hash)
 		return errResp(ErrDecode, "msg %v: %v", msg, err)
 	}
 	if status.GenesisBlock != genesis {
-		return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock, genesis)
+		return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock[:8], genesis[:8])
 	}
 	if int(status.NetworkId) != network {
 		return errResp(ErrNetworkIdMismatch, "%d (!= %d)", status.NetworkId, network)

eth/protocol_test.go

@@ -63,7 +63,7 @@ func testStatusMsgErrors(t *testing.T, protocol int) {
 		},
 		{
 			code: StatusMsg, data: statusData{uint32(protocol), NetworkId, td, currentBlock, common.Hash{3}},
-			wantError: errResp(ErrGenesisBlockMismatch, "0300000000000000000000000000000000000000000000000000000000000000 (!= %x)", genesis),
+			wantError: errResp(ErrGenesisBlockMismatch, "0300000000000000 (!= %x)", genesis[:8]),
 		},
 	}
 

les/peer.go

@@ -367,7 +367,7 @@ func (p *peer) Handshake(td *big.Int, head common.Hash, headNum uint64, genesis
 	}
 
 	if rGenesis != genesis {
-		return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", rGenesis, genesis)
+		return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", rGenesis[:8], genesis[:8])
 	}
 	if int(rNetwork) != p.network {
 		return errResp(ErrNetworkIdMismatch, "%d (!= %d)", rNetwork, p.network)