updateContents(delta) adds additional new line and breaks OT

[benbro]

Sometimes an additional \n is added when applying a delta with quill.updateContents(delta).

Steps for Reproduction

1. Visit http://beta.quilljs.com/
2. Paste this in the console:

quill.setContents([{insert: "ab\nc"}, {insert: "\n", attributes: {list: 'ordered'}}]);
quill.updateContents([
  {retain: 1},
  {delete: 3},
  {retain: 1, attributes: {list: "ordered"}}
]);
quill.getContents();

Expected behavior:

[{insert:"a"},{insert:"\n",attributes:{list:"ordered"}}]

Actual behavior:

[{insert:"a"},{insert:"\n\n",attributes:{list:"ordered"}}]

Platforms:
Firefox 47 on Windows 7

Version:
1.0-beta.4

[benbro]

Verified that the fix work in 1.0 head.
Thanks