MB-8681 hide spinner if the Auth data save failed

moved auth data saving code from SettingSection (settings.js)
to SetupWizard (app.js) since this code is not used outside of the
SetupWizard

Change-Id: I4e1b28a0f6e143efe62b21fd27e15cbad56b8784
Reviewed-on: http://review.couchbase.org/27619
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>