ionic-framework: readonly attribute not rendering on ion-input tags

Short description of the problem:

When conditionally applying the ‘readonly’ attribute to an ion-input, by using the Angular2 syntax [readonly]=“variable”, the ion-input tag does not apply the attribute to the rendered ‘input’ tag.

What behavior are you expecting?

Expect the ‘readonly’ attribute to be rendered on the input tag when “variable” is set to true.

Steps to reproduce:

1. Add an ion input tag with conditional readonly <ion-input [readonly]="isReadonly">
2. Set isReadonly variable to true
3. readonly attribute is not rendered on the resulting input tag

Which Ionic Version? 2.x

Plunker that shows an example of your issue

http://plnkr.co/edit/xKfiA5wR0aoYsm1n6nxe?p=preview

Run ionic info from terminal/cmd prompt: Cordova CLI: 6.1.1 Gulp version: CLI version 3.9.1 Gulp local: Local version 3.9.1 Ionic Framework Version: 2.0.0-beta.4 Ionic CLI Version: 2.0.0-beta.25 Ionic App Lib Version: 2.0.0-beta.15 ios-deploy version: 1.8.6 ios-sim version: 5.0.8 OS: Mac OS X Yosemite Node Version: v4.4.2 Xcode version: Xcode 7.0 Build version 7A220