Changed order of IHttpPromise.then for promise chaining

previously the following code resulted in tmp beeing of type:
ng.IPromise<ng.IPromise<{}>> but it should be just ng.IPromise<{}>:

var tmp = this.$http.get('').then((result) => this.$q.defer().promise);
Merge pull request #2420 from talk4date/ihttppromisefix

AngularJS Binding: Changed order of IHttpPromise.then for promise chaining