Do not use nullptr, old compilers die on it.

doc/ocdoc

@@ -1 +1 @@
-Subproject commit b7218616920517c020837648230b0b9ed502bc08
+Subproject commit a8fc638c26dd47925e66f05fb87cface5dbbbd81

src/gui/folderman.cpp

@@ -672,7 +672,7 @@ void FolderMan::slotStartScheduledFolderSync()
     }
 
     // Find the first folder in the queue that can be synced.
-    Folder* f = nullptr;
+    Folder* f = 0;
     while( !_scheduleQueue.isEmpty() ) {
         f = _scheduleQueue.dequeue();
         Q_ASSERT(f);