bindToController does not bind correctly for multiple directives

The problem occurs when defining multiple directives on the same element. All of the directives use bindToController as an object and scope: true. Only the first directive's controller gets scope bound.

Here is a fiddle showing the bug: https://jsfiddle.net/rds5muzk/

Current console output:

```
first = 2
second = undefined
```

Expected console output:

```
first = 2
second = 4
```
