diff算法里面，没考虑oldChildren为空，newChildren不为空的情况

[L-Chris]

diff.js - 64.js没有考虑oldChildren为空，newChildren不为空的情况，会导致新的children没有渲染

  _.each(oldChildren, function (child, i) {
    var newChild = newChildren[i]
    currentNodeIndex = (leftNode && leftNode.count)
      ? currentNodeIndex + leftNode.count + 1
      : currentNodeIndex + 1
    dfsWalk(child, newChild, currentNodeIndex, patches)
    leftNode = child
  })