fix: background fetch crashing android app

src/app/modules/settings/page/calendar-sync-settings.html

@@ -44,6 +44,12 @@
             'settings.calendar.sync.syncWithCalendar' | translate
           }}</ion-label>
         </ion-item>
+        <!--
+        ~ TODO:
+        ~ background fetch is too unreliable to suggest our users that 
+        ~ they'll get a notification upon change of event/dateseries.
+        ~ This has to be a highly reliable service notifing users via APN/GCM.
+
         <ion-item>
           <ion-toggle
             [disabled]="isWeb"
@@ -59,6 +65,7 @@
             'settings.calendar.sync.eventNotifications' | translate
           }}</ion-label>
         </ion-item>
+        -->
         <ion-item>
           <ion-button
             [disabled]="isWeb || !syncEnabled"