Check both 'ng-model' and 'data-ng-model' attributes in callbacks.update

[fishfacemcgee]

A different incarnation of this was introduced in #293.

[coveralls]

Coverage remained the same when pulling 7112924 on fishfacemcgee:proper-attr-read into aedb58f on angular-ui:master.

[thgreasi]

Great 👍
We should rebase it into one or two semantic commits I think.
I will do it during the merge, if you don't have the time.

[fishfacemcgee]

I'm not really familiar with doing rebases. If you want, I can give it a shot later today and let you know if something went horribly wrong. 😄

[thgreasi]

On then, if it's easier for you, close this PR and open a new one with just the data-ng-model fix.

[thgreasi]

I should have been more specific...
Just open a new PR with one combined commit (or two if you prefer to keep the whitespace commit separate).
If we can write some tests, we can push them in a separate commit.

[fishfacemcgee]

I think I understand now. Closing this as #295 should have what you're looking for now.