NavRing : Fix FC on rotate

onAttachToWindow() is not guaranteed to be called prior to the framework
invoking commands on the panel. This patchset moves over initialization
over to onFinishInflate();

Reproduction steps :

1. Activate search panel view (long press home/swipe up from navbar)
2. Rotate device

Change-Id: I37b5b0de180040bdf1b521bcb8fc014b23c238df