Properly save back-up preferences for repeated canceling

Before this patch, this scenarios didn't yield the expected result:

1) Disable IME, click Apply 2) Enable IME, click Cancel

The expected result is that IME would be disabled, but it was enabled.

This patch re-stashes the preferences when they are saved, so
the last saved preferences are loaded when pressing Cancel.

Change-Id: Ic7abdab165e367d970e6568ba69b25bf7d4f675a
Merge "Properly save back-up preferences for repeated canceling"