gdm: fix handling of removed smartcard at startup

If a smartcard is missing from the reader when we start up,
and the system is configured to disable password authentication,
then we need to ask the user to insert their smartcard.

This commit fixes that.

https://bugzilla.gnome.org/show_bug.cgi?id=740143

js/gdm/util.js

@@ -410,7 +410,7 @@ const ShellUserVerifier = new Lang.Class({
     _updateDefaultService: function() {
         if (this._settings.get_boolean(PASSWORD_AUTHENTICATION_KEY))
             this._defaultService = PASSWORD_SERVICE_NAME;
-        else if (this.smartcardDetected)
+        else if (this._settings.get_boolean(SMARTCARD_AUTHENTICATION_KEY))
             this._defaultService = SMARTCARD_SERVICE_NAME;
         else if (this._haveFingerprintReader)
             this._defaultService = FINGERPRINT_SERVICE_NAME;