Fix google backup/restore functionality

This patch just reverts
Revert "Harden against transiently unavailable backup transports"
This reverts commit 28b6d3829166935f50684c0152a154cd4f1bbb90.

Revert "Handle backup transport registration dynamically"
This reverts commit c46c4a6765196bcabf3ea89771a1f9067b22baad.
Merge "Fix google backup/restore functionality" into kitkat