Explicitly enable backup by default in SDK builds

This change parallels a frameworks/base change that makes the default
backup state at boot "enabled, with LocalTransport as the currently
active transport."  Device vendors who wish to ship the Google backup
transport need to explicitly disable backup by default (it is enabled
when the user agrees to the opt-in disclosure).

Change-Id: I6b0c5c059ef58effd5c121107ea3a5edd9e936cc
1 file changed