QBFT doesn't start when transition block is 0 and no other algorithm config is present

[antonydenyer]

Expected behaviour

Mining to start

Actual behaviour

Mining doesn't start

Steps to reproduce the behaviour

  "config": {
    "chainId": 1337,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "qbft": {
      "epochLength": 30000,
      "blockPeriodSeconds": 5
    },
    "isQuorum": true
  },

works

  "config": {
    "chainId": 1337,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "transitions": [
      {
        "block": 0,
        "algorithm": "qbft",
        "epochLength": 30000,
        "blockPeriodSeconds": 5
      }
    ],
    "isQuorum": true
  },

does not work