Hide drive backup and rate tasks in f-droid

app/src/main/java/org/tasks/preferences/BasicPreferences.java

@@ -201,7 +201,8 @@ public class BasicPreferences extends InjectingPreferenceActivity
 
     //noinspection ConstantConditions
     if (!BuildConfig.FLAVOR.equals("googleplay")) {
-      remove(R.string.p_google_drive_backup);
+      requires(R.string.backup_BPr_header, false, R.string.p_google_drive_backup);
+      requires(R.string.about, false, R.string.rate_tasks);
       requires(R.string.privacy, false, R.string.p_collect_statistics);
     }
   }

app/src/main/res/xml/preferences.xml

@@ -66,6 +66,7 @@
   </PreferenceCategory>
 
   <PreferenceCategory
+    android:key="@string/backup_BPr_header"
     android:title="@string/backup_BPr_header">
 
     <Preference
@@ -111,6 +112,7 @@
   </PreferenceCategory>
 
   <PreferenceCategory
+    android:key="@string/about"
     android:title="@string/about">
 
     <Preference