mat-select model don't update after removing options programmatically

#### Bug, feature request, or proposal:
Bug

#### What is the expected behavior?
I expect to get the model updated and the change event called after remove selected options of the options list.

#### What is the current behavior?
The model don't update and the change event is not called, but visually is updated.

#### What are the steps to reproduce?
1 - http://plnkr.co/edit/RNAeZbaNrtMQRrjC7IDc?p=preview ;
2 - Click on "Remove options";
3 - mat-select visually update;
4 - model dont update and change event is not called;

#### What is the use-case or motivation for changing an existing behavior?
If I change the options for any reason, I expect to get the change events and the model to be updated in order to keep data consistent;

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?
master

#### Is there anything else we should know?
No

从链接的 Plunker 复现开始，研究以编程方式移除选项时 mat-select 的行为。跟踪点击“Remove options”后选定模型和 change event 的响应；完成标准是模型得到更新，并且 change event 被触发以匹配视觉上的选择。

由索引模型根据 Issue 内容生成。