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

resources/js/ext.uls.inputsettings.js

@@ -516,6 +516,9 @@
 				// closure for not losing the scope
 				inputSettings.onSave( result );
 			} );
+
+			// Update the back-up preferences for the case of canceling
+			this.savedRegistry = $.extend( true, {}, $.ime.preferences.registry );
 		}
 	};