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.

Change-Id: I0dbc4a7f041f6925492e7be24d81716b2bd6818f
Merge "Fix google backup/restore functionality" into kitkat