Fix disable shelf kobo sync

cps/shelf.py

@@ -21,20 +21,20 @@
 #  along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 from __future__ import division, print_function, unicode_literals
-from datetime import datetime
+
 import sys
+from datetime import datetime
 
-from flask import Blueprint, request, flash, redirect, url_for
+from flask import Blueprint, flash, redirect, request, url_for
 from flask_babel import gettext as _
-from flask_login import login_required, current_user
+from flask_login import current_user, login_required
+from sqlalchemy.exc import InvalidRequestError, OperationalError
 from sqlalchemy.sql.expression import func, true
-from sqlalchemy.exc import OperationalError, InvalidRequestError
 
-from . import logger, ub, calibre_db, db, config
+from . import calibre_db, config, db, logger, ub
 from .render_template import render_title_template
 from .usermanagement import login_required_if_no_ano
 
-
 shelf = Blueprint('shelf', __name__)
 log = logger.create()
 
@@ -240,8 +240,11 @@ def create_edit_shelf(shelf, title, page, shelf_id=False):
         else:
             shelf.is_public = 0
 
-        if config.config_kobo_sync and "kobo_sync" in to_save:
+        if config.config_kobo_sync:
+            if "kobo_sync" in to_save:
                 shelf.kobo_sync = True
+            else:
+                shelf.kobo_sync = False
 
         if check_shelf_is_unique(shelf, to_save, shelf_id):
             shelf.name = to_save["title"]