Bug 877978 - [Gaia] Use new WebAPI to access iccInfo related attribute/event

Please see [bug 877978](https://bugzilla.mozilla.org/show_bug.cgi?id=877978).

In [bug 875721](https://bugzilla.mozilla.org/show_bug.cgi?id=875721), we move iccInfo related attribute/event from mozMobileConnection to mozIccManager. This pull request is to do corresponding changes in Gaia side.

Thanks