Notify IP address changes to interface observers.

1. Add addressUpdated and addressRemoved methods to
   INetworkManagementEventObserver. (The -Updated method is not
   called -Added because it gets called for both adds and
   changes.) Update all its callers in the tree.
2. Make NetworkManagementService parse IP address notifications
   from NetlinkHandler and call the address{Removed,Updated} on
   its observers.

Bug: 10232006
Change-Id: Ieb185dbba052bdbff03caafc0cf5397a7f04dc6d